使用Intent调用Android系统自身的相机功能

本文演示如何使用Intent调用Android系统自身的相机功能完成拍照。

本例聚焦在相机功能，通过相机拍照以后显示在ImageView中，至于如何保存在文件中或是相册中，将通过另外的文章来说明。

声明权限

使用相机，需要在应用的 AndroidManifest.xml 加入权限声明:

<uses-permission android:name="android.permission.CAMERA"></uses-permission>

在程序中检查权限

在 Android 6 以后，需要在程序中检查用户是否授予应用权限

private void checkPermission() {
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, REQ_CODE_PERSSION_CAMERA);
    }
}

调用相机

使用 MediaStore.ACTION_IMAGE_CAPTURE 作为 action, 构造 Intent，并调用

Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent, REQ_CODE_IMAGE_CAPTURE);

处理Intent的返回

在Intent中，获取图像数据并简单的加载到屏幕中的 ImageView 对象中显示。

@Override
protected void onActivityResult(int reqCode, int resCode, Intent data) {

    if (reqCode == REQ_CODE_IMAGE_CAPTURE && resCode == RESULT_OK) {
        Bitmap bitmap = (Bitmap)data.getExtras().get("data");
        ivwPhoto.setImageBitmap(bitmap);
    } else if (reqCode == REQ_CODE_PERSSION_CAMERA ) {
        Log.d(TAG, "resCode = " + resCode);
    }

    super.onActivityResult(reqCode, resCode, data);
}

完整源代码

1. AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="cn.com.hohistar.tutorial.camerawithintentbasic">

    <uses-permission android:name="android.permission.CAMERA"></uses-permission>

    <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>

</manifest>

2. activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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">

    <Button
        android:id="@+id/btnTakePhoto"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="@string/btnTakePhoto"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/ivwPhoto"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btnTakePhoto"
        app:srcCompat="@drawable/ic_launcher_background" />
</androidx.constraintlayout.widget.ConstraintLayout>

3. MainActivity.java

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MyTAG";

    private static final int REQ_CODE_PERSSION_CAMERA = 1000;
    private static final int REQ_CODE_IMAGE_CAPTURE = 1001;

    @BindView(R.id.ivwPhoto)
    protected ImageView ivwPhoto;

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

        ButterKnife.bind(this);

        checkPermission();
    }

    private void checkPermission() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, REQ_CODE_PERSSION_CAMERA);
        }
    }

    @OnClick(R.id.btnTakePhoto)
    void onBtnTakePhoto() {
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        startActivityForResult(intent, REQ_CODE_IMAGE_CAPTURE);
    }

    @Override
    protected void onActivityResult(int reqCode, int resCode, Intent data) {

        if (reqCode == REQ_CODE_IMAGE_CAPTURE && resCode == RESULT_OK) {
            Bitmap bitmap = (Bitmap)data.getExtras().get("data");
            ivwPhoto.setImageBitmap(bitmap);
        } else if (reqCode == REQ_CODE_PERSSION_CAMERA ) {
            Log.d(TAG, "resCode = " + resCode);
        }

        super.onActivityResult(reqCode, resCode, data);
    }

}