android 动态放大(缩小)图片

通过Matrix设置图片浏览的大小,然后重新生成一个ImageView,指定重新设置的图片

import android.app.Activity;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.Matrix;

import android.graphics.drawable.BitmapDrawable;

import android.os.Bundle;

import android.util.DisplayMetrics;

import android.view.View;

import android.widget.AbsoluteLayout;

import android.widget.Button;

import android.widget.ImageView;

public class MatrixTest extends Activity {

/** Called when the activity is first created. */

private int dis_X,dis_Y;

private float scaleW = 1,scaleH = 1;

private int id;

private Bitmap bm;

private ImageView iv ;

private AbsoluteLayout abs;

private Button btn1;//缩小

private Button btn2;//放大

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

DisplayMetrics dm = new DisplayMetrics();

this.getWindowManager().getDefaultDisplay().getMetrics(dm);

dis_X = dm.widthPixels;

dis_Y = dm.heightPixels-80;

bm = BitmapFactory.decodeResource(this.getResources(), R.drawable.jz);

iv = (ImageView)findViewById(R.id.ImageView01);

iv.setImageResource(R.drawable.jz);

abs = (AbsoluteLayout)findViewById(R.id.layout1);

btn1 = (Button)findViewById(R.id.Button01);//缩小

btn2 = (Button)findViewById(R.id.Button02);//放大

btn1.setOnClickListener(new Button.OnClickListener(){

public void onClick(View v) {

small();

}

});

btn2.setOnClickListener(new Button.OnClickListener(){

public void onClick(View v) {

big();

}

});

}

public void small(){

int bmW = bm.getWidth();

int bmH = bm.getHeight();

//设置图片比例

double scale = 0.8;

//计算缩小比例

scaleW = (float)(scaleW*scale);

scaleH = (float)(scaleH*scale);

//按照比例缩小后生成一个Bitmap

Matrix matrix = new Matrix();

matrix.postScale(scaleW, scaleH);

Bitmap btp = Bitmap.createBitmap(bm,0,0,bmW,bmH,matrix,true);

if(id == 0){

//第一次点击 删除原来默认的ImageView

abs.removeView(iv);

}else{

//第n(n!=0)次点击 删除原来放大或缩小所产生的ImageView

abs.removeView((ImageView)findViewById(id));

}

id++;

ImageView image = new ImageView(this);

image.setId(id);

image.setImageBitmap(btp);

abs.addView(image);

setContentView(abs);

}

public void big(){

int bmW = bm.getWidth();

int bmH = bm.getHeight();

//设置图片比例

double scale = 1.25;

//计算缩小比例

scaleW = (float)(scaleW*scale);

scaleH = (float)(scaleH*scale);

//按照比例放大后生成一个Bitmap

Matrix matrix = new Matrix();

matrix.postScale(scaleW, scaleH);

Bitmap btp = Bitmap.createBitmap(bm,0,0,bmW,bmH,matrix,true);

if(id == 0){

//第一次点击 删除原来默认的ImageView

abs.removeView(iv);

}else{

//第n(n!=0)次点击 删除原来放大或缩小所产生的ImageView

abs.removeView((ImageView)findViewById(id));

}

id++;

ImageView image = new ImageView(this);

image.setId(id);

image.setImageBitmap(btp);

abs.addView(image);

setContentView(abs);

}

}