Android Camera调用摄像机 预览

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效果图：

package com.findai.xkk.ai_interviewer;

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.hardware.Camera;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.AttributeSet;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.TextView;

import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    // Used to load the 'native-lib' library on application startup.
    static {
        System.loadLibrary("native-lib");
    }

    private Camera camera;

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

        // Example of a call to a native method
        TextView tv = (TextView) findViewById(R.id.sample_text);
        SurfaceView sv_camera = findViewById(R.id.sv_camera);
        tv.setText(stringFromJNI());
//        Camera.open();

        sv_camera.getHolder().addCallback(new SurfaceCallback());
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
                == PackageManager.PERMISSION_GRANTED) {
            Log.i("TEST","Granted");
            //init(barcodeScannerView, getIntent(), null);
        } else {
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.CAMERA}, 1);//1 can be another integer
        }
    }

    /**
     * A native method that is implemented by the 'native-lib' native library,
     * which is packaged with this application.
     */
    public native String stringFromJNI();

    private class SurfaceCallback implements SurfaceHolder.Callback{

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            camera = Camera.open(1);
            try {
                followScreenOrientation(getBaseContext(),camera);
                camera.startFaceDetection();

                final Camera.Parameters params = camera.getParameters();
                params.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
                params.setSceneMode(Camera.Parameters.SCENE_MODE_BARCODE);

                camera.setPreviewDisplay(holder);
                camera.startPreview();
                Log.i("camera","create");

            }catch (Exception ex){
                ex.printStackTrace();
            }
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
            Log.i("camera","change");
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            camera.stopPreview();
            camera.setPreviewCallback(null );
            camera.release();
        }
    }

    public static void followScreenOrientation(Context context, Camera camera){
        final int orientation = context.getResources().getConfiguration().orientation;
        if(orientation == Configuration.ORIENTATION_LANDSCAPE) {
            camera.setDisplayOrientation(180);
        }else if(orientation == Configuration.ORIENTATION_PORTRAIT) {
            camera.setDisplayOrientation(90);
        }
    }

}

布局文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical" >

            <SurfaceView
                android:id="@+id/sv_camera"
                android:layout_width="match_parent"
                android:layout_height="300dp" />
            <TextView
                android:id="@+id/sample_text"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Hello World!" />
        </LinearLayout>

    </ScrollView>



</LinearLayout>

AndroidManifest文件：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.findai.xkk.ai_interviewer">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

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

</manifest>