作者:李冰或李冰圆_862 | 来源:互联网 | 2024-11-04 14:29
本文介绍了如何在Android应用中通过使用ZoomControls组件来实现图片的缩放功能。ZoomControls提供了一种简单且直观的方式,让用户可以通过点击放大和缩小按钮来调整图片的显示大小。文章详细讲解了ZoomControls的基本用法、布局设置以及与ImageView的结合使用方法,适合初学者快速掌握AndroidUI设计中的这一重要功能。
ZoomControls控件是一个可以缩放但控件,以下是它但一些主要但方法
hasFocus ():判断焦点
hide ():隐藏
onTouchEvent (MotionEvent event):现这个方法来处理触摸屏移动事件
setIsZoomInEnabled (boolean isEnabled):是否允许放大
setIsZoomOutEnabled (boolean isEnabled):是否允许缩小
setOnZoomInClickListener (View.OnClickListener listener):注册放大监听器
setOnZoomOutClickListener (View.OnClickListener listener):注册缩小监听器
setZoomSpeed (long speed):设置缩放速度
show ():显示
这里面,如果将setIsZoomInEnabled()方法设置为false,那么这个放大的按钮就变成了灰色,不能用了,其实这个控件就是两个按钮而已,只是有外观,没有功能,如果你要放大图片或者缩小图片,还是要在监听事件中实现
开始看代码
main.xml
- "1.0" encoding="utf-8"?>
- "http://schemas.android.com/apk/res/android"
- android:orientation="vertical"
- android:layout_fill_parent"
- android:layout_fill_parent"
- android:id="@+id/layout1"
- >
- android:id="@+id/imgview"
- android:layout_wrap_content"
- android:layout_wrap_content"
- android:src="@drawable/yuanyuan"
- />
-
- android:id="@+id/zoomcontrol"
- android:layout_gravity="bottom"
- android:layout_wrap_content"
- android:layout_wrap_content"
- />
-
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);
-
- DisplayMetrics dm = new DisplayMetrics();
- getWindowManager().getDefaultDisplay().getMetrics(dm);
- displayWidth = dm.widthPixels;
-
- displayHeight = dm.heightPixels;
- bmp = BitmapFactory.decodeResource(getResources(), R.drawable.yuanyuan);
- img = (ImageView)findViewById(R.id.imgview);
-
-
-
- zoom = (ZoomControls)findViewById(R.id.zoomcontrol);
- img = (ImageView)findViewById(R.id.imgview);
- zoom.setIsZoomInEnabled(true);
- zoom.setIsZoomOutEnabled(true);
-
- zoom.setOnZoomInClickListener(new OnClickListener()
- {
- public void onClick(View v)
- {
- int bmpWidth = bmp.getWidth();
- int bmpHeight = bmp.getHeight();
-
- double scale = 1.25;
-
- scaleWidth = (float)(scaleWidth*scale);
- scaleHeight = (float)(scaleHeight*scale);
-
- Matrix matrix = new Matrix();
- matrix.postScale(scaleWidth, scaleHeight);
- Bitmap resizeBmp = Bitmap.createBitmap(bmp,0,0,bmpWidth,bmpHeight,matrix,true);
- img.setImageBitmap(resizeBmp);
-
- }
- });
-
- zoom.setOnZoomOutClickListener(new OnClickListener()
- {
-
- public void onClick(View v) {
- int bmpWidth = bmp.getWidth();
- int bmpHeight = bmp.getHeight();
-
- double scale = 0.8;
-
- scaleWidth = (float)(scaleWidth*scale);
- scaleHeight = (float)(scaleHeight*scale);
-
- 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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