Android多媒体功能开发-使用Camera类拍照的例子

package com.zzk.a1508camera; import android.Manifest; import android.content.Intent; import android.content.pm.PackageManager; import android.hardware.Camera; import android.hardware.Camera.PictureCallback; import android.net.Uri; import android.os.Build; import android.os.Bundle; import android.view.SurfaceView; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.LinearLayout; import android.widget.Toast; import androidx.appcompat.app.AppCompatActivity; import androidx.core.app.ActivityCompat; import androidx.core.content.FileProvider; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; public class MainActivity extends AppCompatActivity { File picFile; Uri picUri; SurfaceView preview; Camera mCamera; int cameraID = 0; boolean isPreviewing = false; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); LinearLayout ll = new LinearLayout(this); ll.setOrientation(LinearLayout.VERTICAL); setContentView(ll); LinearLayout line1 = new LinearLayout(this); line1.setOrientation(LinearLayout.HORIZONTAL); ll.addView(line1); LinearLayout line2 = new LinearLayout(this); line2.setOrientation(LinearLayout.HORIZONTAL); ll.addView(line2); picFile = new File(getExternalFilesDir(null), "picture.jpg"); // 定义多媒体文件的uri，在应用之间传递文件时需要用uri if(Build.VERSION.SDK_INT>=24){ // Android 7 以后不能直接用file uri分享文件，要使用FileProvider String fileProviderAuthority = getPackageName() + ".fileProvider"; // FileProvider的名字，FileProvider在应用配置文件AndroidManifest中定义 // 格式为：content://com.zzk.a1508camera.fileProvider/testdir/picture.jpg, testdir是res/file_paths/file_paths.xml中定义的目录别名 picUri = FileProvider.getUriForFile(MainActivity.this, fileProviderAuthority, picFile); } else { // Android 7 以前可以直接用file uri分享文件 // 格式为：file:///storage/emulated/0/Android/data/com.zzk.a1508camera/files/picture.jpg picUri = Uri.fromFile(picFile); } Button btnOpen = new Button(this); btnOpen.setText("Open"); line1.addView(btnOpen); btnOpen.setOnClickListener(new OnClickListener(){ @Override public void onClick(View arg0) { if (ActivityCompat.checkSelfPermission(getBaseContext(), Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.CAMERA}, 101); return; } open(cameraID); } }); Button btnStartPreview = new Button(this); btnStartPreview.setText("Start Preview"); line1.addView(btnStartPreview); btnStartPreview.setOnClickListener(new OnClickListener(){ @Override public void onClick(View arg0) { if(mCamera!=null) { mCamera.startPreview(); isPreviewing = true; } } }); Button btnTake = new Button(this); btnTake.setText("Take Photo"); line1.addView(btnTake); btnTake.setOnClickListener(new OnClickListener(){ @Override public void onClick(View arg0) { mCamera.takePicture(null, null, new PictureCallback(){ @Override public void onPictureTaken(byte[] arg0, Camera arg1) { FileOutputStream fos; try { fos = new FileOutputStream(picFile); fos.write(arg0); fos.close(); } catch (IOException e) { e.printStackTrace(); } } }); isPreviewing = false; } }); Button btnStopPreview = new Button(this); btnStopPreview.setText("Stop Preview"); line2.addView(btnStopPreview); btnStopPreview.setOnClickListener(new OnClickListener(){ @Override public void onClick(View arg0) { if(mCamera!=null) { mCamera.stopPreview(); isPreviewing = false; } } }); Button btnRelease = new Button(this); btnRelease.setText("Release"); line2.addView(btnRelease); btnRelease.setOnClickListener(new OnClickListener(){ @Override public void onClick(View arg0) { if(mCamera!=null) { mCamera.release(); isPreviewing = false; } } }); Button btnView = new Button(this); btnView.setText("View"); line2.addView(btnView); btnView.setOnClickListener(new OnClickListener(){ @Override public void onClick(View arg0) { if(picFile.exists()){ Intent intent = new Intent(Intent.ACTION_VIEW); intent.setDataAndType(picUri, "image/*"); intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION); // 授予对方读取该文件的权限 startActivity(intent); } } }); Button btnSwitch = new Button(this); btnSwitch.setText("Switch Camera"); ll.addView(btnSwitch); btnSwitch.setOnClickListener(new OnClickListener(){ @Override public void onClick(View arg0) { if(isPreviewing){ cameraID++; if(cameraID>=Camera.getNumberOfCameras()) cameraID = 0; mCamera.stopPreview(); mCamera.release(); open(cameraID); mCamera.startPreview(); } } }); preview = new SurfaceView(this); ll.addView(preview); } @Override public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) { if(requestCode==101) { if(grantResults[0]== PackageManager.PERMISSION_GRANTED){ open(cameraID); } } super.onRequestPermissionsResult(requestCode, permissions, grantResults); } void open(int id){ mCamera = Camera.open(id); Camera.Parameters param = mCamera.getParameters(); //param.setPictureFormat(PixelFormat.JPEG); //param.setPictureSize(1024, 768); mCamera.setParameters(param); mCamera.setDisplayOrientation(90); try { mCamera.setPreviewDisplay(preview.getHolder()); } catch (IOException e) { e.printStackTrace(); } Toast.makeText(getBaseContext(), "Camera opened", Toast.LENGTH_SHORT).show(); } }