自定义View类控制焦点以及Android现实缩小图片的像素和如何通过BitmapFactory读得图片资源，做了笔记。以下代码提供给大伙参考。
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package com.view; import java.util.HashMap; import com.pojo.Constants; import com.test.R; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Matrix; import android.graphics.Paint; import android.util.Log; import android.view.KeyEvent; import android.view.View; import android.view.ViewGroup; public class ADWView extends View { Context myContext = this.getContext(); //读得String.xml里面的资源 private String a = myContext.getString(R.string.app_a); private String b = myContext.getString(R.string.app_b); private String c = myContext.getString(R.string.app_c); private String d = myContext.getString(R.string.app_d); private String e = myContext.getString(R.string.app_e); private int focusID = 0; private Bitmap focusbmp, progressBar_A,progressBar_B,progressBar_C,progressBar_D,progressBar_E,progressBar; private Bitmap bitmap_A,bitmap_B,bitmap_C,bitmap_D,bitmap_E; HashMap<Integer, Integer> progressBarMap = null; public ADWView(Context context) { super(context); this.setFocusable(true); this.requestFocus(); initData(); //焦点图片通过BitmapFactory来得到图片资源R.drawable.shortcut_bg_sel focusbmp = BitmapFactory.decodeResource(this.getResources(), R.drawable.shortcut_bg_sel); } @Override protected void onDraw(Canvas canvas) { //焦点图片初始位置 if (focusbmp != null) { canvas.drawBitmap(focusbmp, this.getPaddingLeft()-20, this.getPaddingTop() + focusID * 100 + 230, null); } super.onDraw(canvas); Paint paint = new Paint(); paint.setColor(Color.WHITE); paint.setTextSize(25); paint.setAntiAlias(true); //获得图片的集合progressBarMap.get(Constants.progressBarValueA) progressBar_A = BitmapFactory.decodeResource(this.getResources(),progressBarMap.get(Constants.progressBarValueA)); progressBar_B = BitmapFactory.decodeResource(this.getResources(),progressBarMap.get(Constants.progressBarValueB)); progressBar_C = BitmapFactory.decodeResource(this.getResources(),progressBarMap.get(Constants.progressBarValueC)); progressBar_D = BitmapFactory.decodeResource(this.getResources(),progressBarMap.get(Constants.progressBarValueD)); progressBar_E = BitmapFactory.decodeResource(this.getResources(),progressBarMap.get(Constants.progressBarValueE)); //获得图片的宽和高 int w = 22000/progressBar_A.getWidth(); int h = 22000/progressBar_A.getHeight(); //刷新图片的像素大小 bitmap_A = progressBar.createScaledBitmap(progressBar_A, w, h, true); bitmap_B = progressBar.createScaledBitmap(progressBar_B, w, h, true); bitmap_C = progressBar.createScaledBitmap(progressBar_C, w, h, true); bitmap_D = progressBar.createScaledBitmap(progressBar_D, w, h, true); bitmap_E = progressBar.createScaledBitmap(progressBar_E, w, h, true); //文字放置在屏幕的位置 canvas.drawText(a + " " + String.valueOf(Constants.A), getPaddingLeft() + 80, getPaddingTop() + 300, paint); //图片的放置在屏幕的位置 canvas.drawBitmap(bitmap_A,getPaddingLeft()+ 244, getPaddingTop() + 247, null); canvas.drawText(b + " " + String.valueOf(Constants.B), getPaddingLeft() + 80, getPaddingTop() + 400, paint); canvas.drawBitmap(bitmap_B, getPaddingLeft()+ 244, getPaddingTop() + 347, null); canvas.drawText(c + " " + String.valueOf(Constants.C), getPaddingLeft() + 80,getPaddingTop() + 500, paint); canvas.drawBitmap(bitmap_C, getPaddingLeft()+ 244, getPaddingTop() + 447, null); canvas.drawText(d + " " + String.valueOf(Constants.D), getPaddingLeft() + 80,getPaddingTop() + 600, paint); canvas.drawBitmap(bitmap_D, getPaddingLeft()+ 244, getPaddingTop() + 547, null); canvas.drawText(e + " " + String.valueOf(Constants.E), getPaddingLeft() + 80,getPaddingTop() + 700, paint); canvas.drawBitmap(bitmap_E, getPaddingLeft()+ 244, getPaddingTop() + 647, null); } public boolean onKeyDown(int keyCode, KeyEvent event) { super.onKeyDown(keyCode, event); switch (keyCode) { case KeyEvent.KEYCODE_DPAD_UP: if (focusID > 0) { focusID--; } else { focusID = 4; } this.invalidate(); break; case KeyEvent.KEYCODE_DPAD_DOWN: if (focusID < 4) { focusID++; } else { focusID = 0; } this.invalidate(); break; //左键的响应 case KeyEvent.KEYCODE_DPAD_LEFT: if (focusID == 0) { if (Constants.A >-10) { Constants.A--; Constants.progressBarValueA--; } else { Constants.A = -10; Constants.progressBarValueA=6; } this.invalidate(); } else if (focusID == 1) { if (Constants.B > -10) { Constants.B--; Constants.progressBarValueB--; } else { Constants.B = -10; Constants.progressBarValueB=6; } this.invalidate(); }else if (focusID == 2) { if (Constants.C > -10) { Constants.C--; Constants.progressBarValueC--; } else { Constants.C = -10; Constants.progressBarValueC=6; } this.invalidate(); }else if (focusID == 3) { if (Constants.D > -10) { Constants.D--; Constants.progressBarValueD--; } else { Constants.D = -10; Constants.progressBarValueD=6; } this.invalidate(); }else if (focusID == 4) { if (Constants.E > -10) { Constants.E--; Constants.progressBarValueE--; } else { Constants.E = -10; Constants.progressBarValueE=6; } this.invalidate(); } break; //右键的响应 case KeyEvent.KEYCODE_DPAD_RIGHT: if (focusID == 0) { if (Constants.A < (10-1)) { Constants.A++; Constants.progressBarValueA++; } else { Constants.A = 10; Constants.progressBarValueA = 26; } this.invalidate(); } else if (focusID == 1) { if (Constants.B < (10 - 1)) { Constants.B++; Constants.progressBarValueB++; } else { Constants.B = 10; Constants.progressBarValueB = 26; } this.invalidate(); }else if (focusID == 2) { if (Constants.C < (10 - 1)) { Constants.C++; Constants.progressBarValueC++; } else { Constants.C = 10; Constants.progressBarValueC = 26; } this.invalidate(); }else if (focusID == 3) { if (Constants.D < (10 - 1)) { Constants.D++; Constants.progressBarValueD++; } else { Constants.D = 10; Constants.progressBarValueD = 26; } this.invalidate(); }else if (focusID == 4) { if (Constants.E < (10 - 1)) { Constants.E++; Constants.progressBarValueE++; } else { Constants.E = 10; Constants.progressBarValueE = 26; } this.invalidate(); } break; //焦点的控制 case KeyEvent.KEYCODE_ENTER: switch (focusID) { case 0: focusID = 1; break; case 1: focusID = 2; break; case 2: focusID = 3; break; case 3: focusID = 4; break; case 4: focusID = 0; break; default: break; } this.invalidate(); break; //退出按键的响应 case KeyEvent.KEYCODE_BACK: ((ViewGroup) (this.getParent())).removeView(this); break; default: break; } return true; } //做一个图片资源的集合 public void initData() { progressBarMap = new HashMap<Integer, Integer>(); progressBarMap.put(1, R.drawable.sound_1); progressBarMap.put(2, R.drawable.sound_2); progressBarMap.put(3, R.drawable.sound_3); progressBarMap.put(4, R.drawable.sound_4); progressBarMap.put(5, R.drawable.sound_5); progressBarMap.put(6, R.drawable.sound_6); progressBarMap.put(7, R.drawable.sound_7); progressBarMap.put(8, R.drawable.sound_8); progressBarMap.put(9, R.drawable.sound_9); progressBarMap.put(10, R.drawable.sound_10); progressBarMap.put(11, R.drawable.sound_11); progressBarMap.put(12, R.drawable.sound_12); progressBarMap.put(13, R.drawable.sound_13); progressBarMap.put(14, R.drawable.sound_14); progressBarMap.put(15, R.drawable.sound_15); progressBarMap.put(16, R.drawable.sound_16); progressBarMap.put(17, R.drawable.sound_17); progressBarMap.put(18, R.drawable.sound_18); progressBarMap.put(19, R.drawable.sound_19); progressBarMap.put(20, R.drawable.sound_20); progressBarMap.put(21, R.drawable.sound_21); progressBarMap.put(22, R.drawable.sound_22); progressBarMap.put(23, R.drawable.sound_23); progressBarMap.put(24, R.drawable.sound_24); progressBarMap.put(25, R.drawable.sound_25); progressBarMap.put(26, R.drawable.sound_26); progressBarMap.put(27, R.drawable.sound_27); progressBarMap.put(28, R.drawable.sound_28); progressBarMap.put(29, R.drawable.sound_29); progressBarMap.put(30, R.drawable.sound_30); progressBarMap.put(31, R.drawable.sound_31); progressBarMap.put(32, R.drawable.sound_32); } }