Android自定义相机实现定时拍照功能

这篇博客为大家介绍Android自定义相机，并且实现倒计时拍照功能。
首先自定义拍照会用到SurfaceView控件显示照片的预览区域，以下是布局文件：
activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent" > 

  <SurfaceView
    android:id="@+id/surface_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent" /> 

  <RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" > 

    <ImageView
      android:id="@+id/start"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      android:layout_alignParentBottom="true"
      android:layout_marginBottom="10dp"
      android:src="@drawable/capture"/> 

    <TextView
      android:id="@+id/count_down"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:layout_gravity="center"
      android:gravity="center"
      android:textSize="80sp"/>
  </RelativeLayout>
</FrameLayout>

MainActivity.java

package com.jackie.timercamera; 

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.hardware.Camera;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView; 

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException; 

public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback,
    View.OnClickListener, Camera.PictureCallback {
  private SurfaceView mSurfaceView;
  private ImageView mIvStart;
  private TextView mTvCountDown; 

  private SurfaceHolder mHolder; 

  private Camera mCamera; 

  private Handler mHandler = new Handler(); 

  private int mCurrentTimer = 10; 

  private boolean mIsSurfaceCreated = false;
  private boolean mIsTimerRunning = false; 

  private static final int CAMERA_ID = 0; //后置摄像头
//  private static final int CAMERA_ID = 1; //前置摄像头
  private static final String TAG = MainActivity.class.getSimpleName(); 

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main); 

    initView();
    initEvent();
  } 

  @Override
  protected void onPause() {
    super.onPause(); 

    stopPreview();
  } 

  private void initView() {
    mSurfaceView = (SurfaceView) findViewById(R.id.surface_view);
    mIvStart = (ImageView) findViewById(R.id.start);
    mTvCountDown = (TextView) findViewById(R.id.count_down);
  } 

  private void initEvent() {
    mHolder = mSurfaceView.getHolder();
    mHolder.addCallback(this); 

    mIvStart.setOnClickListener(this);
  } 

  @Override
  public void surfaceCreated(SurfaceHolder holder) {
    mIsSurfaceCreated = true;
  } 

  @Override
  public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
    startPreview();
  } 

  @Override
  public void surfaceDestroyed(SurfaceHolder holder) {
    mIsSurfaceCreated = false;
  } 

  private void startPreview() {
    if (mCamera != null || !mIsSurfaceCreated) {
      Log.d(TAG, "startPreview will return");
      return;
    } 

    mCamera = Camera.open(CAMERA_ID); 

    Camera.Parameters parameters = mCamera.getParameters();
    int width = getResources().getDisplayMetrics().widthPixels;
    int height = getResources().getDisplayMetrics().heightPixels;
    Camera.Size size = getBestPreviewSize(width, height, parameters);
    if (size != null) {
      //设置预览分辨率
      parameters.setPreviewSize(size.width, size.height);
      //设置保存图片的大小
      parameters.setPictureSize(size.width, size.height);
    } 

    //自动对焦
    parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
    parameters.setPreviewFrameRate(20); 

    //设置相机预览方向
    mCamera.setDisplayOrientation(90); 

    mCamera.setParameters(parameters); 

    try {
      mCamera.setPreviewDisplay(mHolder);
    } catch (Exception e) {
      Log.d(TAG, e.getMessage());
    } 

    mCamera.startPreview();
  } 

  private void stopPreview() {
    //释放Camera对象
    if (mCamera != null) {
      try {
        mCamera.setPreviewDisplay(null);
        mCamera.stopPreview();
        mCamera.release();
        mCamera = null;
      } catch (Exception e) {
        Log.e(TAG, e.getMessage());
      }
    }
  } 

  private Camera.Size getBestPreviewSize(int width, int height,
                      Camera.Parameters parameters) {
    Camera.Size result = null; 

    for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
      if (size.width <= width && size.height <= height) {
        if (result == null) {
          result = size;
        } else {
          int resultArea = result.width * result.height;
          int newArea = size.width * size.height; 

          if (newArea > resultArea) {
            result = size;
          }
        }
      }
    } 

    return result;
  } 

  @Override
  public void onClick(View v) {
    switch (v.getId()) {
      case R.id.start:
        if (!mIsTimerRunning) {
          mIsTimerRunning = true;
          mHandler.post(timerRunnable);
        }
        break;
    }
  } 

  private Runnable timerRunnable = new Runnable() {
    @Override
    public void run() {
      if (mCurrentTimer > 0) {
        mTvCountDown.setText(mCurrentTimer + ""); 

        mCurrentTimer--;
        mHandler.postDelayed(timerRunnable, 1000);
      } else {
        mTvCountDown.setText(""); 

        mCamera.takePicture(null, null, null, MainActivity.this);
        playSound(); 

        mIsTimerRunning = false;
        mCurrentTimer = 10;
      }
    }
  }; 

  @Override
  public void onPictureTaken(byte[] data, Camera camera) {
    try {
      FileOutputStream fos = new FileOutputStream(new File
          (Environment.getExternalStorageDirectory() + File.separator +
              System.currentTimeMillis() + ".png")); 

      //旋转角度，保证保存的图片方向是对的
      Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
      Matrix matrix = new Matrix();
      matrix.setRotate(90);
      bitmap = Bitmap.createBitmap(bitmap, 0, 0,
          bitmap.getWidth(), bitmap.getHeight(), matrix, true);
      bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
      fos.flush();
      fos.close();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } 

    mCamera.startPreview();
  } 

  /**
   *  播放系统拍照声音
   */
  public void playSound() {
    MediaPlayer mediaPlayer = null;
    AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
    int volume = audioManager.getStreamVolume( AudioManager.STREAM_NOTIFICATION); 

    if (volume != 0) {
      if (mediaPlayer == null)
        mediaPlayer = MediaPlayer.create(this,
            Uri.parse("file:///system/media/audio/ui/camera_click.ogg"));
      if (mediaPlayer != null) {
        mediaPlayer.start();
      }
    }
  }
}

有两点需要注意：对于Camera来说，默认是横屏的，所以预览的时候和图片保存的时候都是横屏的，需要调整角度。

设置相机预览方法：

//设置相机预览方向
mCamera.setDisplayOrientation(90);

保存图片的时候调整角度：

效果图如下：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。