序列化手段——parcel例子详解

package com.example.androidtest_parcel;

import android.os.Bundle;
import android.os.Parcel;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity implements OnClickListener{
	
	private Button mWI,mWF,MWD;
	private Button mRI,mRF,mRD;
	private TextView mTextView1;
	private EditText mEdit;
	private Parcel mParcel;
	private int position;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		initView();
		initListener();
		//获取Parcel对象
		mParcel = Parcel.obtain();
	}

	public void initView(){
		mWI= (Button)findViewById(R.id.writeInt);
		mWF= (Button)findViewById(R.id.writeFloat);
		MWD= (Button)findViewById(R.id.writeDouble);
		mRI= (Button)findViewById(R.id.readInt);
		mRF= (Button)findViewById(R.id.readFloat);
		mRD= (Button)findViewById(R.id.readDouble);
		mEdit = (EditText)findViewById(R.id.writePosition);
		mTextView1 = (TextView)findViewById(R.id.textView1);
	}
	
	public void initListener(){
		mWI.setOnClickListener(this);
		mWF.setOnClickListener(this);
		MWD.setOnClickListener(this);
		mRI.setOnClickListener(this);
		mRF.setOnClickListener(this);
		mRD.setOnClickListener(this);
		mTextView1 = (TextView)findViewById(R.id.textView1);
	}
	
	public void showMyParcelDouble(){
		
		int allSize = mParcel.dataCapacity();//当前分配的空间
		int realSize = mParcel.dataSize();//当前实际存储空间
		mParcel.setDataPosition(Integer.parseInt(mEdit.getText().toString()));
		int realPosition  = mParcel.dataPosition();//当前偏移量
		mTextView1.setText("当前分配空间："+allSize+'\n'+
				"当前实际存储空间："+realSize+'\n'+
				"当前偏移量："+realPosition+'\n'+
				'\n'+
				"当前读取到的数为："+mParcel.readDouble());
	}
	public void showMyParcelFloat(){
		
		int allSize = mParcel.dataCapacity();//当前分配的空间
		int realSize = mParcel.dataSize();//当前实际存储空间
		mParcel.setDataPosition(Integer.parseInt(mEdit.getText().toString()));
		int realPosition  = mParcel.dataPosition();//当前偏移量
		mTextView1.setText("当前分配空间："+allSize+'\n'+
				"当前实际存储空间："+realSize+'\n'+
				"当前偏移量："+realPosition+'\n'+
				'\n'+
				"当前读取到的数为："+mParcel.readFloat());
	}
	public void showMyParcelInt(){
		
		int allSize = mParcel.dataCapacity();//当前分配的空间t
		int realSize = mParcel.dataSize();//当前实际存储空间
		mParcel.setDataPosition(Integer.parseInt(mEdit.getText().toString()));
		int realPosition  = mParcel.dataPosition();//当前偏移量
		mTextView1.setText("当前分配空间："+allSize+'\n'+
				"当前实际存储空间："+realSize+'\n'+
				"当前偏移量："+realPosition+'\n'+
				'\n'+
				"当前读取到的数为："+mParcel.readInt());
	}
	
	public void showMyParcel(){
		
		int allSize = mParcel.dataCapacity();//当前分配的空间
		int realSize = mParcel.dataSize();//当前实际存储空间
		int realPosition  = mParcel.dataPosition();//当前偏移量
		mTextView1.setText("当前分配空间："+allSize+'\n'+
				"当前实际存储空间："+realSize+'\n'+
				"当前偏移量："+realPosition+'\n'+
				'\n'+
				"当前没有读取");
	}
	
	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
		switch (v.getId()) {
		case R.id.writeInt:
			mParcel.writeInt(10);
			showMyParcel();
			break;
		case R.id.writeFloat:
			mParcel.writeFloat(20);
			showMyParcel();
			break;
		case R.id.writeDouble:
			mParcel.writeDouble(30);
			showMyParcel();
			break;
		case R.id.readInt:
			showMyParcelInt();			
			break;
		case R.id.readFloat:			
			showMyParcelFloat();
			break;
		case R.id.readDouble:			
			showMyParcelDouble();
			break;

		default:
			break;
		}
		
	}

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

    <Button
        android:id="@+id/writeInt"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="写入一个int" />
    
     <Button
        android:id="@+id/readInt"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="读取一个int" />
    
    </LinearLayout>
    
        <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

    <Button
        android:id="@+id/writeFloat"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="写入一个float" />
    
     <Button
        android:id="@+id/readFloat"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="读取一个float" />
    
    </LinearLayout>


    
        <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

    <Button
        android:id="@+id/writeDouble"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="写入一个double" />
    
     <Button
        android:id="@+id/readDouble"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="读取一个double" />
    
    </LinearLayout>
    
               <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

    <TextView
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="写入偏移量：" 
        android:textSize="20dp"/>
    
     <EditText
        android:id="@+id/writePosition"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:hint="此处输入偏移量" />
    
    </LinearLayout>


    <TextView
        android:layout_marginTop="10dp"
        android:id="@+id/textView1"
        android:layout_width="fill_parent"
        android:layout_height="200dp"/>

</LinearLayout>