android 加载图片

.Android在加载大背景图或者大图片时，经常导致内存溢出（Out of Memory  Error）

   可们可能跟据imageView的宽高来对图片进行压缩，关效的解决（Out of Memory  Error）

  直接上代码  ：

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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

   
    
   <ImageView
       android:src="@drawable/ic_launcher"
       android:id="@+id/image"
       android:layout_height="fill_parent"
       android:layout_width="fill_parent"
       />
	 <Button
        android:onClick="onClick"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />
</RelativeLayout>

java

    ImageView image;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        image=(ImageView) findViewById(R.id.image);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
    public void onClick(View view){
    	//解析图片时需要使用到的参数都封装在这个对象里了
    	Options opt = new Options();
    	//不为像素申请内存，只获取图片宽高
    	opt.inJustDecodeBounds = true;
    	BitmapFactory.decodeResource(getResources(), R.drawable.dog, opt);
    	//拿到图片宽高
    	int imageWidth = opt.outWidth;
    	int imageHeight = opt.outHeight;
    	
    	Display dp = getWindowManager().getDefaultDisplay();
    	//拿到屏幕宽高
	int screenWidth = dp.getWidth();
    	int screenHeight = dp.getHeight();
    	
    	//计算缩放比例
    	int scale = 1;
    	int scaleWidth = imageWidth / screenWidth;
    	int scaleHeight = imageHeight / screenHeight;
    	
    	
    	int max=Math.max(scaleWidth, scaleHeight);
    	
    	if (max>scale) {
    		scale=max;
		}
    	
    	//设置缩放比例
    	opt.inSampleSize = scale;
    	opt.inJustDecodeBounds = false;
    	Bitmap bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.dog, opt);
    	image.setImageBitmap(bitmap);
    }
    
}