Android自定義照相機(jī)詳解

更新時(shí)間：2016年04月08日 15:22:34 作者：一口仨饃的博客

幾乎每個(gè)APP都會(huì)用的相機(jī)功能，下面小編把內(nèi)容整理分享到腳本之家平臺(tái)，供大家參考

幾乎每個(gè)APP都會(huì)用的相機(jī)功能，下面小編把內(nèi)容整理分享到腳本之家平臺(tái)，供大家參考，感興趣的朋友一起學(xué)習(xí)吧！

啟動(dòng)相機(jī)的兩種方式

1.直接啟動(dòng)系統(tǒng)相機(jī)

<code class="hljs avrasm"> Intent intent = new Intent(); 
intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE); 
startActivity(intent);</code>

或者指定返回圖片的名稱mCurrentPhotoFile

<code class="hljs avrasm"> 
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
intent.putExtra(MediaStore.EXTRA_OUTPUT,Uri.fromFile(mCurrentPhotoFile));
startActivityForResult(intent, CAMERA_WITH_DATA);</code>

2.自定義啟動(dòng)相機(jī)

今天以第二種為例。效果圖如下

demo

自定義相機(jī)的一般步驟

創(chuàng)建顯示相機(jī)畫面的布局，Android已經(jīng)為我們選定好SurfaceView 通過SurfaceView#getHolder()獲得鏈接Camera和SurfaceView的SurfaceHolder Camame.open()打開相機(jī) 通過SurfaceHolder鏈接Camera和SurfaceView

一般步驟的代碼演示

<code class="hljs java">public class CameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback, Camera.AutoFocusCallback {
private static final String TAG = "CameraSurfaceView";
private Context mContext;
private SurfaceHolder holder;
private Camera mCamera;
private int mScreenWidth;
private int mScreenHeight;
public CameraSurfaceView(Context context) {
this(context, null);
}
public CameraSurfaceView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CameraSurfaceView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mContext = context;
getScreenMetrix(context);
initView();
}
private void getScreenMetrix(Context context) {
WindowManager WM = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics outMetrics = new DisplayMetrics();
WM.getDefaultDisplay().getMetrics(outMetrics);
mScreenWidth = outMetrics.widthPixels;
mScreenHeight = outMetrics.heightPixels;
}
private void initView() {
holder = getHolder();//獲得surfaceHolder引用
holder.addCallback(this);
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);//設(shè)置類型
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
Log.i(TAG, "surfaceCreated");
if (mCamera == null) {
mCamera = Camera.open();//開啟相機(jī)
try {
mCamera.setPreviewDisplay(holder);//攝像頭畫面顯示在Surface上
} catch (IOException e) {
e.printStackTrace();
}
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
Log.i(TAG, "surfaceChanged");
mCamera.startPreview();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
Log.i(TAG, "surfaceDestroyed");
mCamera.stopPreview();//停止預(yù)覽
mCamera.release();//釋放相機(jī)資源
mCamera = null;
holder = null;
}
@Override
public void onAutoFocus(boolean success, Camera Camera) {
if (success) {
Log.i(TAG, "onAutoFocus success="+success);
}
}
}</code>

添加相機(jī)和自動(dòng)聚焦限權(quán)

<code class="hljs xml"><uses-permission android:name="android.permission.CAMERA">
<uses-feature android:name="android.hardware.camera.autofocus"></uses-feature></uses-permission></code>

將CameraSurfaceView放在布局文件中，這里建議最外層為FrameLayout，后面會(huì)用到。如此，我們便有了一個(gè)沒有照相功能的相機(jī)。初次之外，仔細(xì)觀察相機(jī)顯示畫面，圖片是不是變形嚴(yán)重？那是因?yàn)槲覀冞€沒有為相機(jī)設(shè)置各種參數(shù)。在預(yù)覽前要設(shè)置攝像頭的分辨率、預(yù)覽分辨率和圖片分辨率的寬高比保持一致。這樣圖片才不會(huì)變形。這是個(gè)比較難以理解的部分，想深刻理解還需讀者自己動(dòng)手去實(shí)踐。

<code class="hljs java"> private void setCameraParams(Camera camera, int width, int height) {
Log.i(TAG,"setCameraParams width="+width+" height="+height);
Camera.Parameters parameters = mCamera.getParameters();
// 獲取攝像頭支持的PictureSize列表
List<camera.size> pictureSizeList = parameters.getSupportedPictureSizes();
for (Camera.Size size : pictureSizeList) {
Log.i(TAG, "pictureSizeList size.width=" + size.width + " size.height=" + size.height);
}
/**從列表中選取合適的分辨率*/
Camera.Size picSize = getProperSize(pictureSizeList, ((float) height / width));
if (null == picSize) {
Log.i(TAG, "null == picSize");
picSize = parameters.getPictureSize();
}
Log.i(TAG, "picSize.width=" + picSize.width + " picSize.height=" + picSize.height);
// 根據(jù)選出的PictureSize重新設(shè)置SurfaceView大小
float w = picSize.width;
float h = picSize.height;
parameters.setPictureSize(picSize.width,picSize.height);
this.setLayoutParams(new FrameLayout.LayoutParams((int) (height*(h/w)), height));
// 獲取攝像頭支持的PreviewSize列表
List<camera.size> previewSizeList = parameters.getSupportedPreviewSizes();
for (Camera.Size size : previewSizeList) {
Log.i(TAG, "previewSizeList size.width=" + size.width + " size.height=" + size.height);
}
Camera.Size preSize = getProperSize(previewSizeList, ((float) height) / width);
if (null != preSize) {
Log.i(TAG, "preSize.width=" + preSize.width + " preSize.height=" + preSize.height);
parameters.setPreviewSize(preSize.width, preSize.height);
}
parameters.setJpegQuality(100); // 設(shè)置照片質(zhì)量
if (parameters.getSupportedFocusModes().contains(android.hardware.Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE)) {
parameters.setFocusMode(android.hardware.Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);// 連續(xù)對(duì)焦模式
}
mCamera.cancelAutoFocus();//自動(dòng)對(duì)焦。
mCamera.setDisplayOrientation(90);// 設(shè)置PreviewDisplay的方向，效果就是將捕獲的畫面旋轉(zhuǎn)多少度顯示
mCamera.setParameters(parameters);
}
/**
* 從列表中選取合適的分辨率
* 默認(rèn)w:h = 4:3
*<p>注意：這里的w對(duì)應(yīng)屏幕的height
* h對(duì)應(yīng)屏幕的width</p></camera.size></camera.size></code>
*/ private Camera.Size getProperSize(List pictureSizeList, float screenRatio) { Log.i(TAG, "screenRatio=" + screenRatio); Camera.Size result = null; for (Camera.Size size : pictureSizeList) { float currentRatio = ((float) size.width) / size.height; if (currentRatio - screenRatio == 0) { result = size; break; } } if (null == result) { for (Camera.Size size : pictureSizeList) { float curRatio = ((float) size.width) / size.height; if (curRatio == 4f / 3) {// 默認(rèn)w:h = 4:3 result = size; break; } } } return result; }

進(jìn)去的是屏幕寬高，出來的是調(diào)整好了的參數(shù)。在surfaceChanged方法中執(zhí)行mCamera.startPreview(); 前調(diào)用setCameraParams(mCamera, mScreenWidth, mScreenHeight); 就可以了。最后要在AndroidManifest.xml里設(shè)置activity的方向android:screenOrientation="portrait"代碼里有很多注釋，其中也有我自己調(diào)試時(shí)候的Log，大家可以自己調(diào)試下，看看不同參數(shù)的效果。昨天調(diào)參數(shù)搞到一點(diǎn)多，都在折騰這個(gè)函數(shù)。唉，一把辛酸淚。

身為一個(gè)相機(jī)，居然不能照相？真是太丟臉了！下面給我們的相機(jī)添加上照相的功能。照相核心代碼就一句：mCamera.takePicture(null, null, jpeg);

可以看到takePicture方法有三個(gè)參數(shù)，分別是ShutterCallback、PictureCallback和PictureCallback。這里我們只用了PictureCallback

<code class="hljs java"> // 拍照瞬間調(diào)用
private Camera.ShutterCallback shutter = new Camera.ShutterCallback() {
@Override
public void onShutter() {
Log.i(TAG,"shutter");
}
};
// 獲得沒有壓縮過的圖片數(shù)據(jù)
private Camera.PictureCallback raw = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera Camera) {
Log.i(TAG, "raw");
}
};
//創(chuàng)建jpeg圖片回調(diào)數(shù)據(jù)對(duì)象
private Camera.PictureCallback jpeg = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera Camera) {
BufferedOutputStream bos = null;
Bitmap bm = null;
try {
// 獲得圖片
bm = BitmapFactory.decodeByteArray(data, 0, data.length);
if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
Log.i(TAG, "Environment.getExternalStorageDirectory()="+Environment.getExternalStorageDirectory());
String filePath = "/sdcard/dyk"+System.currentTimeMillis()+".jpg";//照片保存路徑
File file = new File(filePath);
if (!file.exists()){
file.createNewFile();
}
bos = new BufferedOutputStream(new FileOutputStream(file));
bm.compress(Bitmap.CompressFormat.JPEG, 100, bos);//將圖片壓縮到流中
}else{
Toast.makeText(mContext,"沒有檢測(cè)到內(nèi)存卡", Toast.LENGTH_SHORT).show();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
bos.flush();//輸出
bos.close();//關(guān)閉
bm.recycle();// 回收bitmap空間
mCamera.stopPreview();// 關(guān)閉預(yù)覽
mCamera.startPreview();// 開啟預(yù)覽
} catch (IOException e) {
e.printStackTrace();
}
}
}
};</code>

在jpeg的onPictureTaken里。我們將存儲(chǔ)照片信息的byte[] data解析成bitmap，然后轉(zhuǎn)換成JPG格式的圖片保存在SD卡中。注意finally中最后兩句mCamera.stopPreview();// 關(guān)閉預(yù)覽 mCamera.startPreview();// 開啟預(yù)覽上文也提到：當(dāng)調(diào)用camera.takePiture方法后，camera關(guān)閉了預(yù)覽，這時(shí)需要調(diào)用startPreview()來重新開啟預(yù)覽。如果不再次開啟預(yù)覽，則會(huì)一直停留在拍攝照片畫面。為了方便外部調(diào)用拍照。這里我暴露了一個(gè)方法供外部拍照。

<code class="hljs cs"> public void takePicture(){
//設(shè)置參數(shù),并拍照
setCameraParams(mCamera, mScreenWidth, mScreenHeight);
// 當(dāng)調(diào)用camera.takePiture方法后，camera關(guān)閉了預(yù)覽，這時(shí)需要調(diào)用startPreview()來重新開啟預(yù)覽
mCamera.takePicture(null, null, jpeg);
}</code>

在布局文件中添加一個(gè)Button，點(diǎn)擊Button執(zhí)行takePicture()方法。不要忘了添加寫SD卡限權(quán)

<code class="hljs xml"><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission></code>

至此，一個(gè)具有照相并保存拍攝圖片功能的相機(jī)就做出來了。But，我們就此滿足了嗎？要是為了這些簡(jiǎn)單的功能我也不會(huì)寫這篇博客。這只是個(gè)開始

真正的開始

昨天看見別的APP在照相的時(shí)候，屏幕上居然可以顯示像效果圖那樣的框框啦、輔助點(diǎn)啦、圖片bulabulabula~。在網(wǎng)上搜索一番實(shí)現(xiàn)方式，再加上一些自己的理解，構(gòu)成了這篇博客。

上文布局文件一直沒有貼，現(xiàn)在貼出來大家先掃一眼，有些控件會(huì)在接下來展示

<code class="hljs xml"><!--?xml version="1.0" encoding="utf-8"?-->
<framelayout android:layout_height="match_parent" android:layout_width="match_parent" xmlns:android="http://schemas.android.com/apk/res/android">
<com.dyk.cameratest.view.camerasurfaceview android:id="@+id/cameraSurfaceView" android:layout_height="match_parent" android:layout_width="match_parent">
<com.dyk.cameratest.view.rectoncamera android:layout_height="match_parent" android:layout_width="match_parent">
<relativelayout android:layout_height="match_parent" android:layout_width="match_parent">
</relativelayout></com.dyk.cameratest.view.rectoncamera></com.dyk.cameratest.view.camerasurfaceview></framelayout></code><button android:background="#88427ac7" android:id="@+id/takePic" android:layout_alignparentbottom="true" android:layout_centerhorizontal="true" android:layout_height="50dp" android:layout_marginbottom="20dp" android:layout_width="80dp" android:text="拍照" android:textcolor="#aaa"><code class="hljs xml">
</code></button>

布局文件的最外層是個(gè)FrameLayout，我們知道FrameLayout是自帶覆蓋效果的。由來這個(gè)思路接下來就很簡(jiǎn)單了。編程重要的是思想，思想有了，其余的就剩具體的實(shí)現(xiàn)細(xì)節(jié)。

自定義邊邊框框

為了和CameraSurfaceView區(qū)分開，再自定義一個(gè)RectOnCamera專門用來畫邊邊框框這些東西。這樣做還一個(gè)好處是方便維護(hù)，不至于將所有東西都放在一個(gè)View中。

RectOnCamera

<code class="hljs java">package com.dyk.cameratest.view;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
/**
* Created by dyk on 2016/4/7.
*/
public class RectOnCamera extends View {
private static final String TAG = "CameraSurfaceView";
private int mScreenWidth;
private int mScreenHeight;
private Paint mPaint;
private RectF mRectF;
// 圓
private Point centerPoint;
private int radio;
public RectOnCamera(Context context) {
this(context, null);
}
public RectOnCamera(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public RectOnCamera(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
getScreenMetrix(context);
initView(context);
}
private void getScreenMetrix(Context context) {
WindowManager WM = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics outMetrics = new DisplayMetrics();
WM.getDefaultDisplay().getMetrics(outMetrics);
mScreenWidth = outMetrics.widthPixels;
mScreenHeight = outMetrics.heightPixels;
}
private void initView(Context context) {
mPaint = new Paint();
mPaint.setAntiAlias(true);// 抗鋸齒
mPaint.setDither(true);// 防抖動(dòng)
mPaint.setColor(Color.RED);
mPaint.setStrokeWidth(5);
mPaint.setStyle(Paint.Style.STROKE);// 空心
int marginLeft = (int) (mScreenWidth*0.15);
int marginTop = (int) (mScreenHeight * 0.25);
mRectF = new RectF(marginLeft, marginTop, mScreenWidth - marginLeft, mScreenHeight - marginTop);
centerPoint = new Point(mScreenWidth/2, mScreenHeight/2);
radio = (int) (mScreenWidth*0.1);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
mPaint.setColor(Color.RED);
canvas.drawRect(mRectF, mPaint);
mPaint.setColor(Color.WHITE);
Log.i(TAG, "onDraw");
canvas.drawCircle(centerPoint.x,centerPoint.y, radio,mPaint);// 外圓
canvas.drawCircle(centerPoint.x,centerPoint.y, radio - 20,mPaint); // 內(nèi)圓
}
}
</code>

這里簡(jiǎn)單的畫了一個(gè)類似二維碼掃描的框框，還有一個(gè)類似聚焦的內(nèi)外圓。那么問題來了，聚焦的內(nèi)外圓要隨著手指滑而改變位置，而且要有聚焦的效果?？捎趾途哂芯劢构δ艿腃ameraSurfaceView不是同一個(gè)類，不僅如此聚焦內(nèi)外圓還完全覆蓋了CameraSurfaceView。要處理這種問題，需要接口回調(diào)。這就是思想下面的細(xì)節(jié)?，F(xiàn)在雖然確定接口回調(diào)，但還有一個(gè)問題，CameraSurfaceView類和RectOnCamera類中都沒有對(duì)方的對(duì)象或者引用。沒錯(cuò)，通過共同持有RectOnCamera和CameraSurfaceView的Activity可以實(shí)現(xiàn)此功能。下面是具體的實(shí)現(xiàn)方法。

動(dòng)起來

首先，想要隨著手指的滑動(dòng)而改變RectOnCamera的位置肯定是要復(fù)寫onTouchEvent()方法

<code class="hljs cs"> @Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()){
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_MOVE:
case MotionEvent.ACTION_UP:
int x = (int) event.getX();
int y = (int) event.getY();
centerPoint = new Point(x, y);
invalidate();
return true;
}
return true;
}</code>

其次，定義回調(diào)接口

<code class="hljs java"> private IAutoFocus mIAutoFocus;
/** 聚焦的回調(diào)接口 */
public interface IAutoFocus{
void autoFocus();
}
public void setIAutoFocus(IAutoFocus mIAutoFocus) {
this.mIAutoFocus = mIAutoFocus;
}</code>

在onTouchEvent()中return前加入

<code class="hljs cs"> if (mIAutoFocus != null){
mIAutoFocus.autoFocus();
}</code>

至此我們的回調(diào)接口已經(jīng)定義好了，此時(shí)還需要CameraSurfaceView暴露一個(gè)聚焦方法，以便Activity調(diào)用

<code class="hljs cs"> public void setAutoFocus(){
mCamera.autoFocus(this);
}</code>

準(zhǔn)備工作已經(jīng)全部完成，下面請(qǐng)看Activity的具體實(shí)現(xiàn)：

<code class="hljs java">public class MainActivity extends Activity implements View.OnClickListener,RectOnCamera.IAutoFocus{
private CameraSurfaceView mCameraSurfaceView;
private RectOnCamera mRectOnCamera;
private Button takePicBtn;
private boolean isClicked;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
// 全屏顯示
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
mCameraSurfaceView = (CameraSurfaceView) findViewById(R.id.cameraSurfaceView);
mRectOnCamera = (RectOnCamera) findViewById(R.id.rectOnCamera);
takePicBtn= (Button) findViewById(R.id.takePic);
mRectOnCamera.setIAutoFocus(this);
takePicBtn.setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.takePic:
mCameraSurfaceView.takePicture();
break;
default:
break;
}
}
@Override
public void autoFocus() {
mCameraSurfaceView.setAutoFocus();
}
}
</code>

可以看到，MainActivity實(shí)現(xiàn)了IAutoFocus接口，并且在復(fù)寫的IAutoFocus#autoFocus()方法中，調(diào)用了CameraSurfaceView暴露出來的方法setAutoFocus()。至此，在RectOnCamera每次的滑動(dòng)過程中都會(huì)改變聚焦內(nèi)外圓的位置，還會(huì)增加聚焦功能。一心二用甚至一心多用豈不是更好。

好了，Android自定義照相機(jī)教程到此結(jié)束，希望對(duì)大家有所幫助！

腳本之家推薦閱讀：

Android開發(fā)從相機(jī)或相冊(cè)獲取圖片裁剪

Android自定義照相機(jī)倒計(jì)時(shí)拍照

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