自定义控件：瀑布流水字母

 1 <RelativeLayout 
 2     xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     android:background="@android:color/background_light"
 7     tools:context=".MainActivity" >
 8 
 9     <TextView
10         android:layout_width="wrap_content"
11         android:layout_height="wrap_content"
12         android:layout_centerHorizontal="true"
13         android:text="@string/hello_world"
14         android:textColor="@android:color/white" />
15 
16     <com.example.empire.HkTextGroup
17         android:id="@+id/hk_text"
18         android:layout_width="fill_parent"
19         android:layout_height="fill_parent"
20         android:layout_marginTop="20dp"
21         android:background="@android:color/background_dark" />
22 
23 </RelativeLayout>

  1 package com.example.empire;
  2 
  3 import android.content.Context;
  4 import android.graphics.Canvas;
  5 import android.graphics.Color;
  6 import android.graphics.Paint;
  7 import android.graphics.Paint.Align;
  8 import android.graphics.Paint.Style;
  9 import android.os.Handler;
 10 import android.util.AttributeSet;
 11 import android.view.View;
 12 
 13 public class HkTextGroup extends View {
 14 
 15     private char[] counts = new char[] { 
 16             ‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘, ‘F‘, ‘G‘,
 17             ‘H‘, ‘J‘, ‘K‘, ‘L‘, ‘M‘, ‘N‘, ‘O‘ };
 18 
 19     private Paint paint;
 20     private Context ctx;
 21     private Cell[][] cells;
 22     // 像素值
 23     private int textSize = 20;
 24 
 25     public HkTextGroup(Context context, AttributeSet attrs) {
 26         super(context, attrs);
 27         ctx = context;
 28         init();
 29     }
 30 
 31     private void init() {
 32         paint = new Paint();
 33         paint.setAntiAlias(true);
 34         paint.setColor(Color.WHITE);
 35         paint.setTextSize(textSize);// PX值
 36         paint.setTextAlign(Align.LEFT);
 37         paint.setStyle(Style.FILL);
 38 
 39         cells = new Cell[list][row];
 40         for (int j = 0; j < list; j++) {
 41             for (int i = 0; i < row; i++) {
 42                 cells[j][i] = new Cell(i, j);
 43                 cells[j][i].alpha = 0;
 44                 cells[j][i].msg = ""
 45                         + counts[(int) (Math.random() * counts.length)];
 46             }
 47         }
 48     }
 49 
 50     @Override
 51     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 52         super.onMeasure(widthMeasureSpec, heightMeasureSpec);
 53         Utils.logleo("getWidth()::" + getWidth());
 54         Utils.logleo("getHeight()::" + getHeight());
 55 
 56         textSize = getWidth() / 10;
 57         left_bottom = getHeight();
 58     }
 59 
 60     public float left;
 61     public float left_bottom;
 62 
 63     private Handler handler = new Handler() {
 64         public void handleMessage(android.os.Message msg) {
 65             int flag = msg.what;// 0 -- 10
 66 
 67             for (int j = 0; j < list; j++) {
 68 
 69                 for (int i = row - 1; i >= 0; i--) {
 70                     // 1、如果第一行透明度为0，则有一定机率变为255
 71                     // 2、如果中间行透明度为0，不做处理
 72                     // 3、中间行不为0，依次减少一个梯度
 73                     // 4、我上面的一个是255，那么我也是255,而他亮度减1
 74                     Cell cell = cells[j][i];
 75 
 76                     if (i == 0) {
 77                         if (cell.alpha == 0) {
 78                             if (Math.random() * 10 > 9) {
 79                                 cell.alpha = 255;
 80                             }
 81                         } else {
 82                             cell.alpha = cell.alpha - 25 > 0 ? cell.alpha - 25
 83                                     : 0;
 84                         }
 85                     } else if (i > 0 && i <= row - 1) {
 86                         if (cells[j][i - 1].alpha == 255) {
 87                             cell.alpha = 255;
 88                         } else {
 89                             cell.alpha = cell.alpha - 25 > 0 ? cell.alpha - 25
 90                                     : 0;
 91                         }
 92                     }
 93                 }
 94             }
 95             invalidate();
 96 
 97         };
 98     };
 99 
100     private int seed = 0;
101     private int stepCount = 11;
102     /** 行 */
103     private int row = 20;
104     /** 列 */
105     private int list = 20;
106 
107     @Override
108     protected void onDraw(Canvas canvas) {
109 
110         for (int j = 0; j < list; j++) {
111             for (int i = 0; i < row; i++) {
112                 Cell cell = cells[j][i];
113                 // 小机率事件，改变内容
114                 if (Math.random() * 100 > 85) {
115                     cell.msg = ""
116                             + counts[(int) (Math.random() * counts.length)];
117                 }
118                 // 根据透明度确定颜色
119                 if (cell.alpha == 255) {
120                     paint.setColor(Color.WHITE);
121                 } else {
122                     paint.setColor(Color.GREEN);
123                 }
124                 // 设置透明度
125                 paint.setAlpha(cell.alpha);
126 
127                 // 绘制
128                 if (cell.alpha != 0) {
129                     canvas.drawText(cell.msg, cell.j * 15, (float) (cell.i
130                             * textSize * 0.6 + textSize), paint);
131                 }
132             }
133         }
134 
135         // seed = (seed + 1) % stepCount;
136         handler.sendEmptyMessageDelayed(seed, 10);
137     }
138 
139     private class Cell {
140         public Cell(int i, int j) {
141             super();
142             this.i = i;
143             this.j = j;
144         }
145 
146         /** 行 */
147         public int i;
148         /** 列 */
149         public int j;
150         /** 种子 */
151         public int seed;
152         /** 透明度 */
153         public int alpha;
154         public String msg;
155 
156     }
157 
158 }

  1 package com.example.empire;
  2 
  3 import android.content.Context;
  4 import android.graphics.Canvas;
  5 import android.graphics.Color;
  6 import android.graphics.Paint;
  7 import android.graphics.Paint.Align;
  8 import android.graphics.Paint.Style;
  9 import android.os.Handler;
 10 import android.util.AttributeSet;
 11 import android.view.View;
 12 
 13 public class HkText extends View {
 14 
 15     private char[] counts = new char[] { 
 16             ‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘, ‘F‘, ‘G‘,
 17             ‘H‘, ‘J‘, ‘K‘, ‘L‘, ‘M‘, ‘N‘, ‘O‘ };
 18 
 19     private Paint paint;
 20     private Context ctx;
 21 
 22     public HkText(Context context, AttributeSet attrs) {
 23         super(context, attrs);
 24         ctx = context;
 25         init();
 26     }
 27 
 28     /**
 29      * 像素值
 30      */
 31     private int textSize = 20;
 32 
 33     private void init() {
 34         paint = new Paint();
 35         paint.setAntiAlias(true);
 36         paint.setColor(Color.WHITE);
 37         paint.setTextSize(textSize);// PX值
 38         paint.setTextAlign(Align.LEFT);
 40         paint.setStyle(Style.FILL);
 41     }
 42 
 43     // private float sp2px(int sp){
 44     // TypedValue.applyDimension(
 45     // TypedValue.COMPLEX_UNIT_SP, sp, ctx.getResources().getDisplayMetrics());
 46     //
 47     // float px = sp * ctx.getResources().getDisplayMetrics().scaledDensity;
 48     // return px;
 49     // }
 50     //
 51     // private float px2sp(int px){
 52     // float sp = px / ctx.getResources().getDisplayMetrics().scaledDensity;
 53     // return sp;
 54     // }
 55 
 56     @Override
 57  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 58         super.onMeasure(widthMeasureSpec, heightMeasureSpec);
 59         Utils.logleo("getWidth()::" + getWidth());
 60         Utils.logleo("getHeight()::" + getHeight());
 61 
 62         textSize = getWidth() / 10;
 63     }
 64 
 65     public float left = 150;
 66     public float left_bottom = 200;
 67 
 68     private Handler handler = new Handler() {
 69         public void handleMessage(android.os.Message msg) {
 70             // int flag = msg.what;// 0 -- 10
 72             // paint.setColor(Color.BLUE);
 73             invalidate();
 74         };
 75     };
 76 
 77     private int seed = 0;
 79     private int stepCount = 11;
 80 
 81     @Override
 82     protected void onDraw(Canvas canvas) {
 84         left = 10;
 85         left_bottom = 400;
 86         for (int i = 0; i < 20; i++) {
 87 
 88             int seed_tem = seed;
 89 
 90             int alpha = 255 - (i + seed_tem) * 25;
 91             paint.setAlpha(alpha);// 0是没有
 92 
 93             canvas.drawText(counts, i % counts.length, 1, left, 
                     left_bottom,paint);
 96             left_bottom = (float) (left_bottom - textSize * 0.6);
 98         }
 99         seed = (seed + 1) % stepCount;
100         handler.sendEmptyMessageDelayed(seed, 500);
101     }
102 
103 }

 1 package com.example.empire;
 3 import android.util.Log;
 4 
 5 public class Utils {
 7     public static boolean isShow = true;
 9     public static void logleo(String msg) {
10         if (isShow) {
11             Log.i("leo", msg);
12         }
13     }
14 }