玩转Android---UI篇---ZoomControls放大缩小图片
ZoomControls控件是一个可以缩放但控件，效果如下图
以下是它但一些主要但方法
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" android:id="@+id/layout1" ><ImageViewandroid:id="@+id/imgview" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/yuanyuan" /> <ZoomControlsandroid:id="@+id/zoomcontrol"android:layout_gravity="bottom"android:layout_width="wrap_content"android:layout_height="wrap_content" /></LinearLayout>?
ZoomExampleActivity.java
package com.loulijun.zoomcontroltest;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Matrix;import android.os.Bundle;import android.util.DisplayMetrics;import android.view.View;import android.view.View.OnClickListener;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.ZoomControls;public class ZoomExampleActivity extends Activity {private LinearLayout layout1;private ZoomControls zoom;private ImageView img;private int id=0;private int displayWidth;private int displayHeight;private float scaleWidth = 1;private float scaleHeight = 1;private Bitmap bmp; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); layout1 = (LinearLayout)findViewById(R.id.layout1); //取得屏幕分辨率大小 DisplayMetrics dm = new DisplayMetrics(); getWindowManager().getDefaultDisplay().getMetrics(dm); displayWidth = dm.widthPixels; //屏幕高度减去zoomControls的高度 displayHeight = dm.heightPixels; bmp = BitmapFactory.decodeResource(getResources(), R.drawable.yuanyuan); img = (ImageView)findViewById(R.id.imgview); //zoom.hide();隐藏zoomControls //zoom.show();显示zoomCOntrols zoom = (ZoomControls)findViewById(R.id.zoomcontrol); img = (ImageView)findViewById(R.id.imgview); zoom.setIsZoomInEnabled(true); zoom.setIsZoomOutEnabled(true); //图片放大 zoom.setOnZoomInClickListener(new OnClickListener() { public void onClick(View v) { int bmpWidth = bmp.getWidth();int bmpHeight = bmp.getHeight();//设置图片放大但比例double scale = 1.25;//计算这次要放大的比例scaleWidth = (float)(scaleWidth*scale);scaleHeight = (float)(scaleHeight*scale);//产生新的大小但Bitmap对象Matrix matrix = new Matrix();matrix.postScale(scaleWidth, scaleHeight);Bitmap resizeBmp = Bitmap.createBitmap(bmp,0,0,bmpWidth,bmpHeight,matrix,true);img.setImageBitmap(resizeBmp); } }); //图片减小 zoom.setOnZoomOutClickListener(new OnClickListener() {public void onClick(View v) {int bmpWidth = bmp.getWidth();int bmpHeight = bmp.getHeight();//设置图片放大但比例double scale = 0.8;//计算这次要放大的比例scaleWidth = (float)(scaleWidth*scale);scaleHeight = (float)(scaleHeight*scale);//产生新的大小但Bitmap对象Matrix matrix = new Matrix();matrix.postScale(scaleWidth, scaleHeight);Bitmap resizeBmp = Bitmap.createBitmap(bmp,0,0,bmpWidth,bmpHeight,matrix,true);img.setImageBitmap(resizeBmp);} }); }}?效果如下：
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