布局文件:
<LinearLayout 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:orientation="vertical"
>
<ImageView
android:id="@+id/iv"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</LinearLayout>
MainActivit.java
package com.example.day025_exloadertwince;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.Menu;
import android.widget.ImageView;
public class MainActivity extends Activity {
ImageView iv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//初始化控件
iv=(ImageView) findViewById(R.id.iv);
//获取屏幕宽度和高度
int width=getResources().getDisplayMetrics().widthPixels;
int height=getResources().getDisplayMetrics().heightPixels;
//二次采样解析
Bitmap bm=getBitmap(width, height, R.drawable.oom);
iv.setImageBitmap(bm);
}
/**
* 二次采样解析方法
* @param newWidth 屏幕宽度
* @param newHeight屏幕高度
* @param imageId图片id
* @return 返回bitmap
*/
public Bitmap getBitmap(int newWidth,int newHeight,int imageId){
Bitmap bm=null;
BitmapFactory.Options opt=new BitmapFactory.Options();
opt.inJustDecodeBounds=true;
BitmapFactory.decodeResource(getResources(), imageId,opt);
int width=opt.outWidth;
int height=opt.outHeight;
int scaleX=width/newWidth;
int scaleY=height/newHeight;
int scale=scaleX>scaleY?scaleX:scaleY;
opt.inJustDecodeBounds=false;
opt.inSampleSize=scale;
bm= BitmapFactory.decodeResource(getResources(),imageId,opt);
return bm;
}
}