android相机预览
android访问相机使用的是Camera.open 来返回一个Camera对象,设置好显示的视图后,调用Camera的预览功能函数 startPreview,停止预览函数是 stopPreview!
activity_mail.xml布局
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/LinearLayout1" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context="com.ssln.camera.MainActivity" > <VideoView android:id="@+id/videoView1" android:layout_width="match_parent" android:layout_height="300dp" /> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" > <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="打开" /> <Button android:id="@+id/button2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="关闭" /> </LinearLayout> </LinearLayout>
MainActivity.java
package com.ssln.camera; import java.io.IOException; import android.app.Activity; import android.hardware.Camera; import android.os.Bundle; import android.view.SurfaceHolder; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.VideoView; public class MainActivity extends Activity implements OnClickListener { private Camera myCamra; // 相机 private VideoView video; // 显示 private Button btnOpen, btnClose; private boolean isPreview=false; //是否预览 private SurfaceHolder holder; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); video = (VideoView) findViewById(R.id.videoView1); btnOpen = (Button) findViewById(R.id.button1); btnClose = (Button) findViewById(R.id.button2); btnOpen.setOnClickListener(this); btnClose.setOnClickListener(this); holder=video.getHolder(); } @Override public void onClick(View v) { if (v == btnOpen) { initCamera(); } else if (v == btnClose) { if(myCamra!=null && isPreview){ myCamra.stopPreview();//停止预览 myCamra.release(); //释放资源 myCamra=null; isPreview=false; } } } /** * 初始化相机 */ private void initCamera(){ if(!isPreview) { myCamra=Camera.open(); //打开相机设备 } if(myCamra!=null && !isPreview) { try { myCamra.setPreviewDisplay(holder); myCamra.startPreview();//开始预览 } catch (IOException e) { e.printStackTrace(); } isPreview=true; } } }
访问相机是需要权限的,记得加上
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.ssln.camera" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="21" /> <!-- 相机访问权限 --> <uses-permission android:name="android.permission.CAMERA"/>
<!-- 加下下面两句,否则会出现 Fail to connect to camera service. 错误 -->
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
<application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name=".MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
效果预览