Android使用Matrix旋转图片模拟碟片加载过程

今天实现了一个模拟碟片加载过程的小demo，在此展示一下。由于在公司，不好截取动态图片，因此就在这截取两张静态图片看看效果先。

下面简单的将代码列出来。

setp1、准备两张用于旋转的图片，如下：loading_disc.png是第一张图片，loading_light.png是第二张图片。

    

step2、自定义一个View,用来控制这两个图片的旋转。com.oyp.loadingdisk.LoadingDiscView.java

package com.oyp.loadingdisk; 
import java.io.InputStream; 
import android.content.Context; 
import android.content.res.Resources; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.graphics.Canvas; 
import android.graphics.Matrix; 
import android.graphics.Paint; 
import android.graphics.PaintFlagsDrawFilter; 
import android.view.View; 
 
public class LoadingDiscView extends View { 
  private RefreshHandle refreshHandle; 
  private Context context; 
   
  private Bitmap m_bmp_disc = null; 
  private Matrix m_matrix_disc = new Matrix(); 
   
  private Bitmap m_bmp_light = null; 
  private Matrix m_matrix_light = new Matrix(); 
   
  private PaintFlagsDrawFilter mSetfil = null; 
   
  private Paint mypaint = null; 
   
  private float m_scale =1.0f; 
   
  private float m_disc_rot_speed = 0; 
   
  private int m_state_play = 1; 
   
  private float m_disc_max = 20f; 
  public void setRefreshHandle(RefreshHandle refreshHandle) { 
   this.refreshHandle = refreshHandle; 
  } 
  public LoadingDiscView(Context context) { 
   super(context); 
   this.context = context; 
   mSetfil = new PaintFlagsDrawFilter(0, Paint.FILTER_BITMAP_FLAG);//设置画布绘图无锯齿 
   initBitmap(); 
  } 
  public boolean initBitmap() { 
   mypaint = new Paint(); 
   //给Paint加上抗锯齿标志 
   mypaint.setAntiAlias(true);//画笔的抗锯齿（用于线条等） 
   Resources res = context.getResources(); 
   InputStream is = res.openRawResource(R.drawable.loading_disc); 
   m_bmp_disc = BitmapFactory.decodeStream(is); 
   matrixPostTranslate(m_matrix_disc,m_bmp_disc); 
   is = res.openRawResource(R.drawable.loading_light); 
   m_bmp_light = BitmapFactory.decodeStream(is); 
   matrixPostTranslate(m_matrix_light,m_bmp_light); 
   return true; 
  } 
   
  private void matrixPostTranslate(Matrix matrix,Bitmap bitmap) { 
   int tmp_width = bitmap.getWidth(); 
   int tmp_height = bitmap.getHeight(); 
   matrix.postTranslate(-tmp_width / 2, -tmp_height / 2); //设置平移位置 
   matrix.postScale(m_scale, m_scale); //设置缩放比例 
   matrix.postTranslate(123 * m_scale, 146 * m_scale); 
  } 
  protected void onDraw(Canvas canvas) { 
   super.onDraw(canvas); 
   //给Canvas加上抗锯齿标志 
   canvas.setDrawFilter(mSetfil);//图片线条（通用）的抗锯齿 
   canvas.drawBitmap(m_bmp_disc, m_matrix_disc, mypaint); 
   canvas.drawBitmap(m_bmp_light, m_matrix_light, mypaint); 
  } 
  public void update() { 
   if (m_disc_rot_speed > 0.01 || m_state_play == 1){ 
    if (m_state_play == 1 && m_disc_rot_speed<m_disc_max){ 
     m_disc_rot_speed += (m_disc_max+0.5f-m_disc_rot_speed)/30; 
    } 
    else if (m_disc_rot_speed>0.1){ 
     m_disc_rot_speed -= (m_disc_rot_speed)/40; 
    } 
    m_matrix_disc .postRotate(m_disc_rot_speed, 123*m_scale, 146*m_scale); 
    invalidate(); 
   } 
  } 
  public void onPause(){ 
   refreshHandle.stop(); 
  } 
  public void onResume(){ 
   refreshHandle.run(); 
  } 
 } 

step3、写一个Handler用来控制图片的旋转   com.oyp.loadingdisk.RefreshHandle.java

package com.oyp.loadingdisk; 
import android.os.Handler; 
import android.os.Message; 
 
public class RefreshHandle extends Handler { 
 LoadingDiscView loadingDiscView; 
 public RefreshHandle(LoadingDiscView loadingDiscView) { 
  this.loadingDiscView = loadingDiscView; 
  loadingDiscView.setRefreshHandle(this); 
 } 
 public void run() { 
  loadingDiscView.update(); 
  removeCallbacksAndMessages(null); 
  sendEmptyMessageDelayed(0, 65); 
 } 
 public void stop() { 
  removeCallbacksAndMessages(null); 
 } 
 @Override 
 public void handleMessage(Message msg) { 
  switch (msg.what) { 
  case 0: 
   run(); 
   break; 
  } 
 } 
} 

step4、应用布局文件    res/layout/loading.xml

<RelativeLayout 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:background="#382517" 
 tools:context=".MainActivity" 
 > 
 <RelativeLayout 
  android:id="@+id/loading_disc" 
  android:layout_width="match_parent" 
  android:layout_height="wrap_content" 
  android:layout_below="@id/loading_disc"  
  android:paddingLeft="100dp" 
  > 
 </RelativeLayout> 
 <RelativeLayout 
  android:layout_width="fill_parent" 
  android:layout_height="wrap_content" 
  android:layout_marginTop="380dip" > 
  <TextView 
   android:id="@+id/loading_text" 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:layout_centerHorizontal="true" 
   android:singleLine="true" 
   android:textColor="#FFFFFF" 
   android:text="读碟中,请稍后 . . ." 
   android:textSize="20sp" /> 
 </RelativeLayout> 
</RelativeLayout> 

step5、写一个Activity用来装载布局文件，并展示    com.oyp.loadingdisk.LoadingActivity.java

package com.oyp.loadingdisk; 
import android.app.Activity; 
import android.os.Bundle; 
import android.widget.RelativeLayout; 
 
public class LoadingActivity extends Activity { 
 private RelativeLayout motionView; 
 private LoadingDiscView disc_motion; 
 private RefreshHandle refreshHandle; 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.loading); 
  disc_motion = new LoadingDiscView(this); 
  refreshHandle = new RefreshHandle(disc_motion); 
  motionView = (RelativeLayout) findViewById(R.id.loading_disc); 
  motionView.addView(disc_motion); 
  refreshHandle.sendEmptyMessage(0); 
 } 
 @Override 
 protected void onResume() { 
  super.onResume(); 
  disc_motion.onResume(); 
 } 
} 

当然，这里只是模拟碟片加载过程，实际上可以对代码进行处理，使碟片加载过程完毕后，启动相应的界面来展示碟片中的视频、图像、音乐资源等，但是这里不便写出来。

关于源代码，您可以通过 https://github.com/ouyangpeng/LoadingDisk 来免费察看和下载代码。

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