HDU1237 简单计算器【栈】+【逆波兰式】

时间：2014-06-01 17:56:15 阅读：502 评论：0 收藏：0 [点我收藏+]

版本：1.0

日期：2014.5.17 2014.6.1

在介绍SwitchButton之前，先来看一下系统Button是如何实现的。源码如下：

@RemoteView
public class Button extends TextView {
    public Button(Context context) {
        this(context, null);
    }

    public Button(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.buttonStyle);
    }

    public Button(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
        super.onInitializeAccessibilityEvent(event);
        event.setClassName(Button. class.getName());
    }

    @Override
    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
        super.onInitializeAccessibilityNodeInfo(info);
        info.setClassName(Button. class.getName());
    }
}

是直接继承于TextView，所不同的是在构造方法中添加了Button的样式，并且在初始化可见性方面交由Button类自己来处理。虽然Button的实现比较简单，但是它的子类并不是这样。看一下：

直接子类只有有一个，CompoundButton。它是一个抽象类，而实现这个类的控件正是CheckBox, RadioButton, Switch, ToggleButton这四个，所以先重点说一下它。源码如下：

/**
 * <p>
 * A button with two states, checked and unchecked. When the button is pressed
 * or clicked, the state changes automatically.
 * </p>
 *
 * <p><strong>XML attributes </strong></p>
 * <p>
 * See {@link android.R.styleable#CompoundButton
 * CompoundButton Attributes}, {@link android.R.styleable#Button Button
 * Attributes}, {@link android.R.styleable#TextView TextView Attributes}, {@link
 * android.R.styleable #View View Attributes}
 * </p>
 */
public abstract class CompoundButton extends Button implements Checkable {
    private boolean mChecked ;
    private int mButtonResource ;
    private boolean mBroadcasting ;
    private Drawable mButtonDrawable;
    private OnCheckedChangeListener mOnCheckedChangeListener;
    private OnCheckedChangeListener mOnCheckedChangeWidgetListener ;

    private static final int[] CHECKED_STATE_SET = {
        R.attr.state_checked
    };

    public CompoundButton(Context context) {
        this(context, null);
    }

    public CompoundButton(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CompoundButton(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        TypedArray a =
                context.obtainStyledAttributes(
                        attrs, com.android.internal.R.styleable.CompoundButton, defStyle, 0);

        Drawable d = a.getDrawable(com.android.internal.R.styleable.CompoundButton_button);
        if (d != null ) {
            setButtonDrawable(d);
        }

        boolean checked = a
                .getBoolean(com.android.internal.R.styleable.CompoundButton_checked, false);
        setChecked(checked);

        a.recycle();
    }

    public void toggle() {
        setChecked(! mChecked);
    }

    @Override
    public boolean performClick() {
        /*
         * XXX: These are tiny, need some surrounding ‘expanded touch area‘,
         * which will need to be implemented in Button if we only override
         * performClick()
         */

        /* When clicked, toggle the state */
        toggle();
        return super .performClick();
    }

    @ViewDebug.ExportedProperty
    public boolean isChecked() {
        return mChecked ;
    }

    /**
     * <p>Changes the checked state of this button.</p>
     *
     * @param checked true to check the button, false to uncheck it
     */
    public void setChecked(boolean checked) {
        if (mChecked != checked) {
            mChecked = checked;
            refreshDrawableState();
            notifyViewAccessibilityStateChangedIfNeeded(
                    AccessibilityEvent.CONTENT_CHANGE_TYPE_UNDEFINED );

            // Avoid infinite recursions if setChecked() is called from a listener
            if (mBroadcasting ) {
                return;
            }

            mBroadcasting = true ;
            if (mOnCheckedChangeListener != null) {
                mOnCheckedChangeListener.onCheckedChanged(this, mChecked);
            }
            if (mOnCheckedChangeWidgetListener != null) {
                mOnCheckedChangeWidgetListener .onCheckedChanged(this, mChecked);
            }

            mBroadcasting = false ;           
        }
    }

    /**
     * Register a callback to be invoked when the checked state of this button
     * changes.
     *
     * @param listener the callback to call on checked state change
     */
    public void setOnCheckedChangeListener(OnCheckedChangeListener listener) {
        mOnCheckedChangeListener = listener;
    }

    /**
     * Register a callback to be invoked when the checked state of this button
     * changes. This callback is used for internal purpose only.
     *
     * @param listener the callback to call on checked state change
     * @hide
     */
    void setOnCheckedChangeWidgetListener(OnCheckedChangeListener listener) {
        mOnCheckedChangeWidgetListener = listener;
    }

    /**
     * Interface definition for a callback to be invoked when the checked state
     * of a compound button changed.
     */
    public static interface OnCheckedChangeListener {
        /**
         * Called when the checked state of a compound button has changed.
         *
         * @param buttonView The compound button view whose state has changed.
         * @param isChecked  The new checked state of buttonView.
         */
        void onCheckedChanged(CompoundButton buttonView, boolean isChecked);
    }

    /**
     * Set the background to a given Drawable, identified by its resource id.
     *
     * @param resid the resource id of the drawable to use as the background
     */
    public void setButtonDrawable(int resid) {
        if (resid != 0 && resid == mButtonResource ) {
            return;
        }

        mButtonResource = resid;

        Drawable d = null;
        if (mButtonResource != 0) {
            d = getResources().getDrawable(mButtonResource );
        }
        setButtonDrawable(d);
    }

    /**
     * Set the background to a given Drawable
     *
     * @param d The Drawable to use as the background
     */
    public void setButtonDrawable(Drawable d) {
        if (d != null ) {
            if (mButtonDrawable != null) {
                mButtonDrawable.setCallback(null);
                unscheduleDrawable( mButtonDrawable);
            }
            d.setCallback( this);
            d.setVisible(getVisibility() == VISIBLE, false);
            mButtonDrawable = d;
            setMinHeight(mButtonDrawable .getIntrinsicHeight());
        }

        refreshDrawableState();
    }

    @Override
    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
        super.onInitializeAccessibilityEvent(event);
        event.setClassName(CompoundButton.class .getName());
        event.setChecked( mChecked);
    }

    @Override
    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
        super.onInitializeAccessibilityNodeInfo(info);
        info.setClassName(CompoundButton.class .getName());
        info.setCheckable( true);
        info.setChecked( mChecked);
    }

    @Override
    public int getCompoundPaddingLeft() {
        int padding = super.getCompoundPaddingLeft();
        if (!isLayoutRtl()) {
            final Drawable buttonDrawable = mButtonDrawable;
            if (buttonDrawable != null) {
                padding += buttonDrawable.getIntrinsicWidth();
            }
        }
        return padding;
    }

    @Override
    public int getCompoundPaddingRight() {
        int padding = super.getCompoundPaddingRight();
        if (isLayoutRtl()) {
            final Drawable buttonDrawable = mButtonDrawable;
            if (buttonDrawable != null) {
                padding += buttonDrawable.getIntrinsicWidth();
            }
        }
        return padding;
    }

    /**
     * @hide
     */
    @Override
    public int getHorizontalOffsetForDrawables() {
        final Drawable buttonDrawable = mButtonDrawable ;
        return (buttonDrawable != null) ? buttonDrawable.getIntrinsicWidth() : 0;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        final Drawable buttonDrawable = mButtonDrawable ;
        if (buttonDrawable != null) {
            final int verticalGravity = getGravity() & Gravity.VERTICAL_GRAVITY_MASK ;
            final int drawableHeight = buttonDrawable.getIntrinsicHeight();
            final int drawableWidth = buttonDrawable.getIntrinsicWidth();

            int top = 0;
            switch (verticalGravity) {
                case Gravity.BOTTOM :
                    top = getHeight() - drawableHeight;
                    break;
                case Gravity.CENTER_VERTICAL :
                    top = (getHeight() - drawableHeight) / 2;
                    break;
            }
            int bottom = top + drawableHeight;
            int left = isLayoutRtl() ? getWidth() - drawableWidth : 0;
            int right = isLayoutRtl() ? getWidth() : drawableWidth;

            buttonDrawable.setBounds(left, top, right, bottom);
            buttonDrawable.draw(canvas);
        }
    }

    @Override
    protected int[] onCreateDrawableState(int extraSpace) {
        final int [] drawableState = super.onCreateDrawableState(extraSpace + 1);
        if (isChecked()) {
            mergeDrawableStates(drawableState, CHECKED_STATE_SET);
        }
        return drawableState;
    }

    @Override
    protected void drawableStateChanged() {
        super.drawableStateChanged();
       
        if (mButtonDrawable != null) {
            int[] myDrawableState = getDrawableState();
           
            // Set the state of the Drawable
            mButtonDrawable.setState(myDrawableState);
           
            invalidate();
        }
    }

    @Override
    protected boolean verifyDrawable(Drawable who) {
        return super .verifyDrawable(who) || who == mButtonDrawable;
    }

    @Override
    public void jumpDrawablesToCurrentState() {
        super.jumpDrawablesToCurrentState();
        if (mButtonDrawable != null) mButtonDrawable.jumpToCurrentState();
    }

    static class SavedState extends BaseSavedState {
        boolean checked ;

        /**
         * Constructor called from {@link CompoundButton#onSaveInstanceState()}
         */
        SavedState(Parcelable superState) {
            super(superState);
        }
       
        /**
         * Constructor called from {@link #CREATOR}
         */
        private SavedState(Parcel in) {
            super(in);
            checked = (Boolean)in.readValue( null);
        }

        @Override
        public void writeToParcel(Parcel out, int flags) {
            super.writeToParcel(out, flags);
            out.writeValue( checked);
        }

        @Override
        public String toString() {
            return "CompoundButton.SavedState{"
                    + Integer.toHexString(System.identityHashCode(this))
                    + " checked=" + checked + "}" ;
        }

        public static final Parcelable.Creator<SavedState> CREATOR
                = new Parcelable.Creator<SavedState>() {
            public SavedState createFromParcel(Parcel in) {
                return new SavedState(in);
            }

            public SavedState[] newArray(int size) {
                return new SavedState[size];
            }
        };
    }

    @Override
    public Parcelable onSaveInstanceState() {
        // Force our ancestor class to save its state
        setFreezesText( true);
        Parcelable superState = super.onSaveInstanceState();

        SavedState ss = new SavedState(superState);

        ss. checked = isChecked();
        return ss;
    }

    @Override
    public void onRestoreInstanceState(Parcelable state) {
        SavedState ss = (SavedState) state;
 
        super.onRestoreInstanceState(ss.getSuperState());
        setChecked(ss. checked);
        requestLayout();
    }
}

先从构造方法开始，在构造方法中，

 public CompoundButton(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        TypedArray a =
                context.obtainStyledAttributes(
                        attrs, com.android.internal.R.styleable.CompoundButton, defStyle, 0);

        Drawable d = a.getDrawable(com.android.internal.R.styleable.CompoundButton_button);
        if (d != null ) {
            setButtonDrawable(d);
        }

        boolean checked = a
                .getBoolean(com.android.internal.R.styleable.CompoundButton_checked, false);
        setChecked(checked);

        a.recycle();
    }

先是从attrs中读取定义的属性，一个是Drawable用于设置背景；一个是布尔类型变量用于判断是否check过。设置背景使用的是setButtonDrawable()方法，代码如下：

/**
     * Set the background to a given Drawable
     *
     * @param d The Drawable to use as the background
     */
    public void setButtonDrawable(Drawable d) {
        if (d != null ) {
            if (mButtonDrawable != null) {
                mButtonDrawable.setCallback(null);
                unscheduleDrawable( mButtonDrawable);
            }
            d.setCallback( this);
            d.setVisible(getVisibility() == VISIBLE, false);
            mButtonDrawable = d;
            setMinHeight(mButtonDrawable .getIntrinsicHeight());
        }

        refreshDrawableState();
    }

这个方法写的就比较完善，可以作为一个学习的典范。首先判断传递过来的Drawable是否为空，如果不为空并且默认的Drawable也不为空，那么取消默认Drawable的callback，然后调用unscheduleDrawable方法。这个方法代码如下：

 /**
     * Unschedule any events associated with the given Drawable.  This can be
     * used when selecting a new Drawable into a view, so that the previous
     * one is completely unscheduled.
     *
     * @param who The Drawable to unschedule.
     *
     * @see #drawableStateChanged
     */
    public void unscheduleDrawable(Drawable who) {
        if (mAttachInfo != null && who != null) {
            mAttachInfo.mViewRootImpl .mChoreographer.removeCallbacks(
                    Choreographer.CALLBACK_ANIMATION, null, who);
        }
    }

从方法注释中可以看出它的用途，正是更换Drawable时候使用的。接下来开始重新设置Drawable，包括回调、可见性、最小高度。最后调用refreshDrawableState()方法，这个是View类的方法，用于更新Drawable状态。

然后再回过头看一下setChecked(checked)方法，这个用于设置check，也就是button的点击状态。代码如下：

/**
     * <p>Changes the checked state of this button.</p>
     *
     * @param checked true to check the button, false to uncheck it
     */
    public void setChecked( boolean checked) {
        if (mChecked != checked) {
            mChecked = checked;
            refreshDrawableState();
            notifyViewAccessibilityStateChangedIfNeeded(
                    AccessibilityEvent.CONTENT_CHANGE_TYPE_UNDEFINED );

            // Avoid infinite recursions if setChecked() is called from a listener
            if (mBroadcasting ) {
                return;
            }

            mBroadcasting = true ;
            if (mOnCheckedChangeListener != null) {
                mOnCheckedChangeListener.onCheckedChanged(this, mChecked);
            }
            if (mOnCheckedChangeWidgetListener != null) {
                mOnCheckedChangeWidgetListener .onCheckedChanged(this, mChecked);
            }
            mBroadcasting = false ;           
        }
    }

在这个方法中多出了一个接口，这个接口真是check的一个回调接口，代码如下：

/**
     * Interface definition for a callback to be invoked when the checked state
     * of a compound button changed.
     */
    public static interface OnCheckedChangeListener {
        /**
         * Called when the checked state of a compound button has changed.
         *
         * @param buttonView The compound button view whose state has changed.
         * @param isChecked  The new checked state of buttonView.
         */
        void onCheckedChanged(CompoundButton buttonView, boolean isChecked);
    }

这种回调接口在Android中处处可见，之前的文章也有介绍过。但是在上面的方法，它使用了一个mBroadcasting变量，进而巧妙地避免了重复递归的问题，大家自己感受一下。

然后就是ondraw()方法了，把之前的drawable画出来。代码如下：

  @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        final Drawable buttonDrawable = mButtonDrawable ;
        if (buttonDrawable != null) {
            final int verticalGravity = getGravity() & Gravity.VERTICAL_GRAVITY_MASK ;
            final int drawableHeight = buttonDrawable.getIntrinsicHeight();
            final int drawableWidth = buttonDrawable.getIntrinsicWidth();

            int top = 0;
            switch (verticalGravity) {
                case Gravity.BOTTOM :
                    top = getHeight() - drawableHeight;
                    break;
                case Gravity.CENTER_VERTICAL :
                    top = (getHeight() - drawableHeight) / 2;
                    break;
            }
            int bottom = top + drawableHeight;
            int left = isLayoutRtl() ? getWidth() - drawableWidth : 0;
            int right = isLayoutRtl() ? getWidth() : drawableWidth;

            buttonDrawable.setBounds(left, top, right, bottom);
            buttonDrawable.draw(canvas);
        }
    }

看得出来，在onDrawable()方法中，最主要的部分还是如何确定上下左右四个参数。确定完后就可以画出来了。但是，CompoundButton是一个抽象类，并不能直接使用，那看一下它的子类是如何实现的：

1、CheckBox

 public class CheckBox extends CompoundButton {
    public CheckBox(Context context) {
        this(context, null);
    }
   
    public CheckBox(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.checkboxStyle);
    }

    public CheckBox(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
        super.onInitializeAccessibilityEvent(event);
        event.setClassName(CheckBox. class.getName());
    }

    @Override
    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
        super.onInitializeAccessibilityNodeInfo(info);
        info.setClassName(CheckBox. class.getName());
    }
}

和Button的实现差不多，使用了一个自己的样式。并且也是重写了那两个方法。再来看一下RadioButton，

public class RadioButton extends CompoundButton {
   
    public RadioButton(Context context) {
        this(context, null);
    }
   
    public RadioButton(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.radioButtonStyle);
    }

    public RadioButton(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    /**
     * {@inheritDoc}
     * <p>
     * If the radio button is already checked, this method will not toggle the radio button.
     */
    @Override
    public void toggle() {
        // we override to prevent toggle when the radio is already
        // checked (as opposed to check boxes widgets)
        if (!isChecked()) {
            super.toggle();
        }
    }

    @Override
    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
        super.onInitializeAccessibilityEvent(event);
        event.setClassName(RadioButton. class.getName());
    }

    @Override
    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
        super.onInitializeAccessibilityNodeInfo(info);
        info.setClassName(RadioButton. class.getName());
    }
}

和CheckBox实现差不多，区别在于多重写了一个方法，用于防止按钮被重复点击。另外还有ToggleButton以及Switch，前者实现也比较简单，后者稍微麻烦了一些，感兴趣可以自己分析。

最后切入正题，看看滑动Button要如何实现呢？首先看一下效果图：

图1-1

图1-2

图1-1所示的滑动Button实现的思路是这样的，背景图片有开和关的文字，一个按钮在其上面左右滑动，遮住相应的部分，使其在一个位置时候只能看到一个开关。

如图1-3，在实现的时候，先画一个开关背景图片只，然后在其上面画一个按钮，滑动开关的时候对上面的按钮进行处理即可。

准备：

1、按钮图片

2、背景图片

编码：

在自定义滑动按钮控件的时候，可以有多种选择，可以继承于Button，也可以继承于Button的子类，也可以继承于View类等。我们知道滑动按钮是一个很简单的控件，就是左右滑动改变显示内容，不需要其他的额外东西在里面，所以直接继承于View来实现即可。如果继承于系统的一些控件，那么有很多东西用不到，会造成浪费。

1、定义一个类继承于View，初始化构造方法，在构造方法中加载图片及其信息。

2、重写onMeasure()方法，计算控件的大小。

3、重写onTouchEvent()方法，对滑动事件进行判别处理。

4、定义接口，实现回调。

5、重写onDraw()方法，动态画出按钮。

代码如下：

/**
*
*/
package com.kince.slidebutton;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;

/**
* @author kince
* @category 左右手势滑动button
* @serial 1.0.0
* @since 2014.5.17
* @see http://blog.csdn.net/wangjinyu501
*
*/
public class SlideButton extends View {

     private Bitmap slideBitMap;// 滑动图片
     private Bitmap switchBitMap;// 背景图片

     private int slideBitMapWidth;// 滑动图片宽度
     private int switchBitMapWidth;// 背景图片宽度
     private int switchBitMapHeight;// 背景图片高度

     private boolean currentState;// 开关状态
     private boolean isSliding = false; // 是否正在滑动中

     private int currentX; // 当前开关的位置

     private OnToggleStateChangedListener mChangedListener;// 回调接口

     /**
     * @param context
     *            在java代码中直接调用使用此构造方法
     */
     public SlideButton(Context context) {
          this(context, null);
          // TODO Auto-generated constructor stub
     }

     /**
     * @param context
     * @param attrs
     *            在xml中使用要用到这个方法
     */
     public SlideButton(Context context, AttributeSet attrs) {
          this(context, attrs, 0);
          // TODO Auto-generated constructor stub
     }

     /**
     * @param context
     * @param attrs
     * @param defStyleAttr
     *            指定一个样式
     */
     public SlideButton(Context context, AttributeSet attrs, int defStyleAttr) {
          super(context, attrs, defStyleAttr);
          initBitmap();
     }

     /**
     * @category 加载背景图片以及开关图片 然后获取各自的宽高
     *
     */
     private void initBitmap() {
          // TODO Auto-generated method stub
          slideBitMap = BitmapFactory.decodeResource(getResources(),
                    R.drawable.slide_button_background);
          switchBitMap = BitmapFactory.decodeResource(getResources(),
                    R.drawable.switch_background);
          slideBitMapWidth = slideBitMap.getWidth();
          switchBitMapWidth = switchBitMap.getWidth();
          switchBitMapHeight = switchBitMap.getHeight();
          Log.i("switchBitMapWidth", switchBitMapWidth + "");
     }

     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
          // TODO Auto-generated method stub
          super.onMeasure(widthMeasureSpec, heightMeasureSpec);
          setMeasuredDimension(switchBitMapWidth, switchBitMapHeight);// 设置控件的宽高
     }

     @Override
     protected void onDraw(Canvas canvas) {
          // 绘制button背景图片
          canvas.drawBitmap(switchBitMap, 0, 0, null);
          // 绘制滑动开关
          if (isSliding) {// 如果当前状态是滑动中 则动态绘制开关
               int dis = currentX - slideBitMapWidth / 2;
               if (dis < 0) {
                    dis = 0;
               } else if (dis > switchBitMapWidth - slideBitMapWidth) {
                    dis = switchBitMapWidth - slideBitMapWidth;
               }
               canvas.drawBitmap(slideBitMap, dis, 0, null);
          } else {
               if (currentState) { // 绘制开关为开的状态
                    canvas.drawBitmap(slideBitMap, switchBitMapWidth
                              - slideBitMapWidth, 0, null);
               } else { // 绘制开关为关的状态
                    canvas.drawBitmap(slideBitMap, 0, 0, null);
               }
          }
          super.onDraw(canvas);
     }

     @Override
     public boolean onTouchEvent(MotionEvent event) {
          // 手势识别 判断滑动方向
          int action = event.getAction();
          switch (action) {
          case MotionEvent.ACTION_DOWN:
               isSliding = true;
               currentX = (int) event.getX();
               break;

          case MotionEvent.ACTION_MOVE:
               currentX = (int) event.getX();
               Log.i("currentX", currentX + "");

               break;
          case MotionEvent.ACTION_UP:
               isSliding = false;
               int bgCenter = switchBitMapWidth / 2;
               boolean state = currentX > bgCenter; // 改变后的状态
               if (state != currentState && mChangedListener != null) {// 添加回调
                    mChangedListener.onToggleStateChanged(state);
               }
               currentState = state;
               break;
          default:
               break;
          }
          invalidate();
          return true;
     }

     public OnToggleStateChangedListener getmChangedListener() {
          return mChangedListener;
     }

     public void setmChangedListener(
               OnToggleStateChangedListener mChangedListener) {
          this.mChangedListener = mChangedListener;
     }

     public boolean isToggleState() {
          return currentState;
     }

     public void setToggleState(boolean currentState) {
          this.currentState = currentState;
     }

}

回调接口，

  package com.kince.slidebutton;

/**
 * @author kince
 *
 */
public interface OnToggleStateChangedListener {

     /**
      * @category
      * @param state
      */
     public void onToggleStateChanged(boolean state);

}

Activity代码，

package com.kince.slidebutton;

import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import android.os.Build;

public class MainActivity extends ActionBarActivity {

     @Override
     protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);

          if (savedInstanceState == null) {
               getSupportFragmentManager().beginTransaction()
                         .add(R.id.container, new PlaceholderFragment()).commit();
          }
     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {

          // Inflate the menu; this adds items to the action bar if it is present.
          getMenuInflater().inflate(R.menu.main, menu);
          return true;
     }

     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
          // Handle action bar item clicks here. The action bar will
          // automatically handle clicks on the Home/Up button, so long
          // as you specify a parent activity in AndroidManifest.xml.
          int id = item.getItemId();
          if (id == R.id.action_settings) {
               return true;
          }
          return super.onOptionsItemSelected(item);
     }

     /**
     * A placeholder fragment containing a simple view.
     */
     public static class PlaceholderFragment extends Fragment implements
               OnToggleStateChangedListener {

          private SlideButton slidebutton;

          public PlaceholderFragment() {
          }

          @Override
          public View onCreateView(LayoutInflater inflater, ViewGroup container,
                    Bundle savedInstanceState) {
               View rootView = inflater.inflate(R.layout.fragment_main, container,
                         false);
               slidebutton = (SlideButton) rootView.findViewById(R.id.slidebutton1);
               // 设置一下开关的状态
               slidebutton.setToggleState(true); // 设置开关的状态为打开
               slidebutton.setmChangedListener(this);
               return rootView;
          }

          @Override
          public void onToggleStateChanged(boolean state) {
               // TODO Auto-generated method stub
               FragmentActivity activity = getActivity();
               if (state) {
                    Toast.makeText(activity, "开关打开", 0).show();
               } else {
                    Toast.makeText(activity, "开关关闭", 0).show();
               }
          }
     }

}

未完待续。

HDU1237 简单计算器【栈】+【逆波兰式】,布布扣,bubuko.com

HDU1237 简单计算器【栈】+【逆波兰式】

标签：android c style class blog code

原文地址：http://blog.csdn.net/u012846486/article/details/27962853

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周排行

HDU1237 简单计算器 【栈】+【逆波兰式】

HDU1237 简单计算器【栈】+【逆波兰式】