Android应用开发揭秘的第13个程序5_8_MatrixRotateImg修改版和高仿版的源码注释

最新推荐文章于 2025-02-25 16:57:11 发布

翻译最新推荐文章于 2025-02-25 16:57:11 发布 · 701 阅读

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本文介绍了一个简单的Android应用程序，用于演示如何使用Matrix类来旋转图片。通过监听键盘输入，可以实时改变图片的旋转角度，实现流畅的旋转效果。

//学会运用Matrix 旋转图片

//Matrix mMatrix = new Matrix(); mMatrix.reset();

//mBitQQ = ((BitmapDrawable) getResources().getDrawable(R.drawable.qq)).getBitmap();
// mMatrix.setRotate(Angle);
/* 按mMatrix得旋转构建新的Bitmap */
// Bitmap mBitQQ2 = Bitmap.createBitmap(mBitQQ, 0, 0, BitQQwidth,BitQQheight, mMatrix, true);

Activity01.java

package com.MatrixRotateImg;

import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;

public class Activity01 extends Activity
{
private GameView mGameView = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
  super.onCreate(savedInstanceState);

  mGameView = new GameView(this);

  setContentView(mGameView);
}
public boolean onKeyUp(int keyCode, KeyEvent event)
{
  super.onKeyUp(keyCode, event);
  return true;
}
public boolean onKeyDown(int keyCode, KeyEvent event)
{
  if ( mGameView == null )
  {
   return false;
  }
  if ( keyCode == KeyEvent.KEYCODE_BACK)
  {
   this.finish();
   return true;
  }
  return mGameView.onKeyDown(keyCode,event);
}
}

GameView.java

package pak.GfMatrixRotateImg;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.View;

public class GameView extends View implements Runnable
{
/* 声明Bitmap对象 */
Bitmap mBitQQ = null;
int BitQQwidth = 0;
int BitQQheight = 0;

float Angle = 0.0f;

/* 构建Matrix对象 */
Matrix mMatrix = new Matrix();

public GameView(Context context)
{
  super(context);

  /* 装载资源 */
  mBitQQ = ((BitmapDrawable) getResources().getDrawable(R.drawable.qq)).getBitmap();

  /* 得到图片的宽度和高度 */
  BitQQwidth = mBitQQ.getWidth();
  BitQQheight = mBitQQ.getHeight();

  /* 开启线程 */
  new Thread(this).start();
}

public void onDraw(Canvas canvas)
{
  super.onDraw(canvas);

  /* 重置mMatrix */
  mMatrix.reset();

  /* 设置旋转 */
  mMatrix.setRotate(Angle);

  /* 按mMatrix得旋转构建新的Bitmap */
  Bitmap mBitQQ2 = Bitmap.createBitmap(mBitQQ, 0, 0, BitQQwidth,BitQQheight, mMatrix, true);

  /* 绘制旋转之后的图片 */
  GameView.drawImage(canvas, mBitQQ2, (320-BitQQwidth)/2, 10);

  mBitQQ2 = null;
}

// 触笔事件
public boolean onTouchEvent(MotionEvent event)
{
  return true;
}

// 按键按下事件
public boolean onKeyDown(int keyCode, KeyEvent event)
{
  //左方向键
  if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT)
  {
   Angle--;
  }
  //右方向键
  else if (keyCode == KeyEvent.KEYCODE_DPAD_RIGHT)
  {
    Angle++;
  }
  return true;
}

// 按键弹起事件
public boolean onKeyUp(int keyCode, KeyEvent event)
{
return false;
}

public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event)
{
  return true;
}

/**
* 线程处理
*/
public void run()
{
  while (!Thread.currentThread().isInterrupted())
  {
   try
   {
    Thread.sleep(100);
   }
   catch (InterruptedException e)
   {
    Thread.currentThread().interrupt();
   }
   //使用postInvalidate可以直接在线程中更新界面
   postInvalidate();
  }
}

/**
* 绘制一个Bitmap
* @param canvas 画布
* @param bitmap 图片
* @param x   屏幕上的x坐标
* @param y   屏幕上的y坐标
*/
public static void drawImage(Canvas canvas, Bitmap bitmap, int x, int y)
{
  /* 绘制图像 */
  canvas.drawBitmap(bitmap, x, y, null);
}
}

Gf_MatrixRotateImgActivity.java

package pak.GfMatrixRotateImg;

import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;

public class Gf_MatrixRotateImgActivity extends Activity {
private GameView mGameView = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
  super.onCreate(savedInstanceState);

  mGameView = new GameView(this);

  setContentView(mGameView);
}
public boolean onKeyUp(int keyCode, KeyEvent event)
{
  super.onKeyUp(keyCode, event);
  return true;
}
public boolean onKeyDown(int keyCode, KeyEvent event)
{
  if ( mGameView == null )
  {
   return false;
  }
  if ( keyCode == KeyEvent.KEYCODE_BACK)
  {
   this.finish();
   return true;
  }
  return mGameView.onKeyDown(keyCode,event);
}
}