Android開發_Camera應用

1、通過調用系統的照相機實現照相功能

1）將拍照的圖片存到本地文件,然後再讀取顯示

public class MainActivity extends Activity {
	private Button btn;
	private ImageView iv;
	private File file = null;
	private static final int REQUEST_CODE = 1;

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

		btn = (Button) findViewById(R.id.btn);
		iv = (ImageView) findViewById(R.id.iv);

		// 設置按鈕單擊事件
		btn.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View v) {
				// 在sdcard卡中創建一個文件夾,要獲取相應的權限
				File dir = new File(Environment.getExternalStorageDirectory(),
						"pictures");
				if (!dir.exists()) {
					dir.mkdir();
				}

				file = new File(dir, System.currentTimeMillis() + ".jpg");

				if (!file.exists()) {
					try {
						file.createNewFile();
					} catch (IOException e) {
						e.printStackTrace();
					}
				}

				// 調用系統的照相機
				Intent i = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
				i.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
				startActivityForResult(i, REQUEST_CODE);
			}
		});
	}

	// 獲取Activity返回結果的方法
	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		switch (requestCode) {
		case REQUEST_CODE:
			iv.setImageURI(Uri.fromFile(file));
			break;
		default:
			break;
		}
		super.onActivityResult(requestCode, resultCode, data);
	}
}

2）直接讀取拍照的數據,並且顯示

public class Main extends Activity implements OnClickListener
{
	private ImageView imageView;
	
	@Override
	public void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		
		Button btnTakePicture = (Button)findViewById(R.id.btnTakePicture);
		btnTakePicture.setOnClickListener(this);
		
		imageView = (ImageView)findViewById(R.id.imageview);
		
	}
	protected void onActivityResult(int requestCode, int resultCode, Intent data)
	{
		if(requestCode == 1)
		{
			if(resultCode == Activity.RESULT_OK)
			{
				Bitmap cameraBitmap = (Bitmap)data.getExtras().get("data");
				imageView.setImageBitmap(cameraBitmap);
				
			}
		}
	}
	
    public void onClick(View view)
    {
    	Intent intent =new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    	startActivityForResult(intent, 1);
    	
    }
	
}

相應的佈局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/iv"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

    <Button
        android:id="@+id/btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="開始拍照" />

</LinearLayout>

2、通過調用Camera類實現照相功能

要使用照相機,需要獲取相應的權限<uses-permission android:name="android.permission.CAMERA" />

public class MainActivity extends Activity {
	private SurfaceView sv;
	private Camera camera;// 照相機對象
	private Button btn;// 照相按鈕

	private Callback callback = new Callback() {

		@Override
		public void surfaceDestroyed(SurfaceHolder arg0) {
			stopPreview();
		}

		@Override
		public void surfaceCreated(SurfaceHolder arg0) {
			startPreview();
		}

		@Override
		public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2,
				int arg3) {

		}
	};

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

		sv = (SurfaceView) findViewById(R.id.sv);
		sv.getHolder().addCallback(callback);

		btn = (Button) findViewById(R.id.btn);
		btn.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View arg0) {
				// 照相機拍照
				camera.takePicture(null, null, new Camera.PictureCallback() {
					// 拍完照片後的回調方法
					@Override
					public void onPictureTaken(byte[] data, Camera camera) {
						String path = null;
						if ((path = saveFile(data)) != null) {
							Intent i = new Intent(MainActivity.this,
									ImagePreviewActivity.class);
							i.putExtra("path", path);
							startActivity(i);
						} else {
							// 保存文件失敗
							Toast.makeText(MainActivity.this, "保存照片失敗!",
									Toast.LENGTH_SHORT).show();
						}
					}
				});
			}
		});
	}

	// 開始預覽
	private void startPreview() {
		// 打開照相機
		camera = Camera.open();
		try {
			camera.setPreviewDisplay(sv.getHolder());
			camera.setDisplayOrientation(90);
			camera.startPreview();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	// 結束預覽
	private void stopPreview() {
		camera.stopPreview();
		camera.release();
	}

	// 保存照片的方法
	private String saveFile(byte[] bytes) {
		try {
			// createTempFile()在android 4.x版本後默認的存儲路徑爲：/data/data/應用包名/cache
			// 而之前的版本該方法會把文件存儲在sd上
			File f = File.createTempFile("img", "");
			FileOutputStream fos = new FileOutputStream(f);
			fos.write(bytes);
			fos.flush();
			fos.close();
			return f.getAbsolutePath();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}
}

public class ImagePreviewActivity extends Activity {
	private ImageView iv;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		iv = new ImageView(this);
		setContentView(iv);
		// 獲取圖片的路徑
		String path = getIntent().getStringExtra("path");
		if (path != null) {
			// 顯示圖片
			iv.setImageURI(Uri.fromFile(new File(path)));
		}
	}

}

相應的佈局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <SurfaceView
        android:id="@+id/sv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

    <Button
        android:id="@+id/btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="拍照" />

</LinearLayout>