Android 调用相机拍摄照片或者从相册选取照片

//MainActivity.java
package com.lfork.a98620.cameraalbumtest;

import android.Manifest;
import android.content.ContentUris;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v4.content.FileProvider;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity {

public static final int TAKE_PHOTO = 1;
public static final int CHOOSE_PHOTO = 2;
private ImageView picture;
private Uri imageUri;
private static final String TAG = "MainActivity";

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

Button takePhoto = (Button) findViewById(R.id.take_photo);
Button chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);
picture = (ImageView) findViewById(R.id.picture);
takePhoto.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//创建file对象用于储存拍摄的照片
File outputImage = new File(getExternalCacheDir(), "output_image.jpg");

try{
if (outputImage.exists()){
outputImage.delete();
}
outputImage.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}

if (Build.VERSION.SDK_INT >= 24) {
imageUri = FileProvider.getUriForFile(MainActivity.this, "com.lfork.a98620.cameraalbumtest.fileprovider", outputImage);
} else {
imageUri = Uri.fromFile(outputImage);
}

//启动相机程序
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
//将url关联到相机拍摄的图片上面
intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
startActivityForResult(intent, TAKE_PHOTO);
}
});

chooseFromAlbum.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {

//6.0及以上的系统在使用危险权限的时候必须进行运行时权限处理
ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);

} else {
4000

openAlbum();
}
}
});
}

private void openAlbum() {
Intent intent = new Intent("android.intent.action.GET_CONTENT");
intent.setType("image/*");
startActivityForResult(intent, CHOOSE_PHOTO);
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
switch (requestCode) {
case 1:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
openAlbum();
} else {
Toast.makeText(this, "You denied the permission", Toast.LENGTH_SHORT).show();
}
break;
default:
break;
}
}

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode){
case TAKE_PHOTO:
if (resultCode == RESULT_OK){
try{
//将照片显示出来
//getContentResolver  根据传入的和uri相关联的数据  来访问指定的内容提供器当中的内容
Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
picture.setImageBitmap(bitmap);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
break;
case CHOOSE_PHOTO:
if (resultCode == RESULT_OK) {
//判断手机系统版本号
if (Build.VERSION.SDK_INT >= 19) {
//4.4及以上版本使用这个方法处理图片
handleImageOnKitKat(data);
} else {
handleImageBeforeKitKat(data);
}
}
break;
default:
break;
}
}

private void handleImageOnKitKat(Intent data) {
String imagePath = null;
Uri uri = data.getData();
if (DocumentsContract.isDocumentUri(this, uri)) {
//如果是document 类型的uri  ， 则通过document id 处理
String docId = DocumentsContract.getDocumentId(uri);
if ("com.android.providers.media.documents".equals(uri.getAuthority())){
String id = docId.split(":")[1];  //解析出数字格式的id
String selection = MediaStore.Images.Media._ID + "=" + id;
imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);

} else if ("com.android.providers.downloads.documents".equals(uri.getAuthority())){
Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads//public_downloads"), Long.valueOf(docId));
imagePath = getImagePath(contentUri, null);
}
} else if ("content".equalsIgnoreCase(uri.getScheme())){
//如果是Content类型的Uri 则通过普通的方式处理
imagePath = getImagePath(uri, null);
} else if ("file".equalsIgnoreCase(uri.getScheme())) {
//如果是file类型的Uri ，直接获取图片路径即可
imagePath = uri.getPath();
}
displayImage(imagePath);//根据图片路径显示图片;
}

private void handleImageBeforeKitKat(Intent data) {
Uri uri = data.getData();
String imagePath = getImagePath(uri, null);
displayImage(imagePath);
}
private String getImagePath(Uri uri, String selection) {
String path = null;
//通过Uri 和 selection 来获取真实的图片路径
Cursor cursor = getContentResolver().query(uri, null, selection, null, null);
if (cursor != null) {
if (cursor.moveToFirst()) {
path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
}
cursor.close();
}
return path;
}

private void displayImage(String imagePath) {
Log.d(TAG, "displayImage: test");
if (imagePath != null) {
Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
picture.setImageBitmap(bitmap);
} else {
Toast.makeText(this, "failed to get image", Toast.LENGTH_SHORT).show();
}

}

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.lfork.a98620.cameraalbumtest.MainActivity">

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

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

<ImageView
android:id="@+id/picture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"/>

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.lfork.a98620.cameraalbumtest">

<!--为了兼容Android 4.4以前的程序 这里需要设置 SD卡访问权限-->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

<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>

<provider
android:authorities="com.lfork.a98620.cameraalbumtest.fileprovider"
android:name="android.support.v4.content.FileProvider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths"/>
</provider>
</application>

</manifest>

file_paths

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path name="my_images" path=""/>
</paths>