Android獲取本地相冊圖片和拍照獲取圖片的實現方法

2019-12-12 03:22:54

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來源：轉載

供稿：網友

需求：從本地相冊找圖片，或通過調用系統相機拍照得到圖片。

容易出錯的地方：

1、當我們指定了照片的uri路徑，我們就不能通過data.getData();來獲取uri，而應該直接拿到uri(用全局變量或者其他方式)然后設置給imageView

imageView.setImageURI(uri);

2、我發現手機前置攝像頭拍出來的照片只有幾百KB，直接用imageView.setImageURI(uri);沒有很大問題，但是后置攝像頭拍出來的照片比較大，這個時候使用imageView.setImageURI(uri);就容易出現 out of memory（oom）錯誤，我們需要先把URI轉換為Bitmap,再壓縮bitmap，然后通過imageView.setImageBitmap(bitmap);來顯示圖片。

3、將照片存放到SD卡中后，照片不能立即出現在系統相冊中，因此我們需要發送廣播去提醒相冊更新照片。

4、這里用到了sharepreference，要注意用完之后移除緩存。

代碼：

MainActivity:

package com.sctu.edu.test;import android.content.Intent;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.net.Uri;import android.os.Bundle;import android.os.Environment;import android.provider.MediaStore;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import android.widget.ImageView;import com.sctu.edu.test.tools.ImageTools;import java.io.File;import java.io.IOException;import java.text.SimpleDateFormat;import java.util.Date;public class MainActivity extends AppCompatActivity {  private static final int PHOTO_FROM_GALLERY = 1;  private static final int PHOTO_FROM_CAMERA = 2;  private ImageView imageView;  private File appDir;  private Uri uriForCamera;  private Date date;  private String str = "";  private SharePreference sharePreference;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    //Android不推薦使用全局變量，我在這里使用了sharePreference    sharePreference = SharePreference.getInstance(this);    imageView = (ImageView) findViewById(R.id.imageView);  }  //從相冊取圖片  public void gallery(View view) {    Intent intent = new Intent();    intent.setType("image/*");    intent.setAction(Intent.ACTION_GET_CONTENT);    startActivityForResult(intent, PHOTO_FROM_GALLERY);  }  //拍照取圖片  public void camera(View view) {    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);    uriForCamera = Uri.fromFile(createImageStoragePath());    sharePreference.setCache("uri", String.valueOf(uriForCamera));        /**     * 指定了uri路徑，startActivityForResult不返回intent，     * 所以在onActivityResult()中不能通過data.getData()獲取到uri;     */    intent.putExtra(MediaStore.EXTRA_OUTPUT, uriForCamera);    startActivityForResult(intent, PHOTO_FROM_CAMERA);  }  @Override  protected void onActivityResult(int requestCode, int resultCode, Intent data) {    super.onActivityResult(requestCode, resultCode, data);    //第一層switch    switch (requestCode) {      case PHOTO_FROM_GALLERY:        //第二層switch        switch (resultCode) {          case RESULT_OK:            if (data != null) {              Uri uri = data.getData();              imageView.setImageURI(uri);            }            break;          case RESULT_CANCELED:            break;        }        break;      case PHOTO_FROM_CAMERA:        if (resultCode == RESULT_OK) {          Uri uri = Uri.parse(sharePreference.getString("uri"));          updateDCIM(uri);          try {            //把URI轉換為Bitmap，并將bitmap壓縮，防止OOM(out of memory)            Bitmap bitmap = ImageTools.getBitmapFromUri(uri, this);            imageView.setImageBitmap(bitmap);          } catch (IOException e) {            e.printStackTrace();          }          removeCache("uri");        } else {          Log.e("result", "is not ok" + resultCode);        }        break;      default:        break;    }  }  /**   * 設置相片存放路徑，先將照片存放到SD卡中，再操作   *   * @return   */  private File createImageStoragePath() {    if (hasSdcard()) {      appDir = new File("/sdcard/testImage/");      if (!appDir.exists()) {        appDir.mkdirs();      }      SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMddHHmmss");      date = new Date();      str = simpleDateFormat.format(date);      String fileName = str + ".jpg";      File file = new File(appDir, fileName);      return file;    } else {      Log.e("sd", "is not load");      return null;    }  }    /**   * 將照片插入系統相冊，提醒相冊更新   *   * @param uri   */  private void updateDCIM(Uri uri) {    Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);    intent.setData(uri);    this.sendBroadcast(intent);    Bitmap bitmap = BitmapFactory.decodeFile(uri.getPath());    MediaStore.Images.Media.insertImage(getContentResolver(), bitmap, "", "");  }  /**   * 判斷SD卡是否可用   *   * @return   */  private boolean hasSdcard() {    if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {      return true;    } else {      return false;    }  }  /**   * 移除緩存   *   * @param cache   */  private void removeCache(String cache) {    if (sharePreference.ifHaveShare(cache)) {      sharePreference.removeOneCache(cache);    } else {      Log.e("this cache", "is not exist.");    }  }}

ImageTools:

package com.sctu.edu.test.tools;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.net.Uri;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.io.InputStream;public class ImageTools {  /**   * 通過uri獲取圖片并進行壓縮   *   * @param uri   * @param activity   * @return   * @throws IOException   */  public static Bitmap getBitmapFromUri(Uri uri, Activity activity) throws IOException {    InputStream inputStream = activity.getContentResolver().openInputStream(uri);    BitmapFactory.Options options = new BitmapFactory.Options();    options.inJustDecodeBounds = true;    options.inDither = true;    options.inPreferredConfig = Bitmap.Config.ARGB_8888;    BitmapFactory.decodeStream(inputStream, null, options);    inputStream.close();    int originalWidth = options.outWidth;    int originalHeight = options.outHeight;    if (originalWidth == -1 || originalHeight == -1) {      return null;    }    float height = 800f;    float width = 480f;    int be = 1; //be=1表示不縮放    if (originalWidth > originalHeight && originalWidth > width) {      be = (int) (originalWidth / width);    } else if (originalWidth < originalHeight && originalHeight > height) {      be = (int) (originalHeight / height);    }    if (be <= 0) {      be = 1;    }    BitmapFactory.Options bitmapOptinos = new BitmapFactory.Options();    bitmapOptinos.inSampleSize = be;    bitmapOptinos.inDither = true;    bitmapOptinos.inPreferredConfig = Bitmap.Config.ARGB_8888;    inputStream = activity.getContentResolver().openInputStream(uri);    Bitmap bitmap = BitmapFactory.decodeStream(inputStream, null, bitmapOptinos);    inputStream.close();    return compressImage(bitmap);  }  /**   * 質量壓縮方法   *   * @param bitmap   * @return   */  public static Bitmap compressImage(Bitmap bitmap) {    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, byteArrayOutputStream);    int options = 100;    while (byteArrayOutputStream.toByteArray().length / 1024 > 100) {      byteArrayOutputStream.reset();      //第一個參數 ：圖片格式 ，第二個參數： 圖片質量，100為最高，0為最差 ，第三個參數：保存壓縮后的數據的流      bitmap.compress(Bitmap.CompressFormat.JPEG, options, byteArrayOutputStream);      options -= 10;    }    ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());    Bitmap bitmapImage = BitmapFactory.decodeStream(byteArrayInputStream, null, null);    return bitmapImage;  }}

AndroidMainfest.xml:

<?xml version="1.0" encoding="utf-8"?><manifest package="com.sctu.edu.test"   xmlns:android="http://schemas.android.com/apk/res/android"> <uses-feature  android:name="android.hardware.camera"  android:required="true"  /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <uses-permission android:name="android.permission.CAMERA"/> <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/> <uses-permission android:name="com.miui.whetstone.permission.ACCESS_PROVIDER"/> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/> <uses-feature android:name="android.hardware.camera.autofocus" /> <application  android:allowBackup="true"  android:icon="@mipmap/ic_launcher"  android:label="@string/app_name"  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>

activity_main.xml:

<?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:layout_width="match_parent" android:layout_height="match_parent" android:background="#fff" android:orientation="vertical" tools:context="com.sctu.edu.test.MainActivity"> <Button  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:text="從圖庫找圖片"  android:id="@+id/gallery"  android:onClick="gallery"  android:background="#ccc"  android:textSize="20sp"  android:padding="10dp"  android:layout_marginLeft="30dp"  android:layout_marginTop="40dp"  /> <Button  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:text="拍照獲取圖片"  android:id="@+id/camera"  android:onClick="camera"  android:background="#ccc"  android:textSize="20sp"  android:padding="10dp"  android:layout_marginLeft="30dp"  android:layout_marginTop="40dp"  /> <ImageView  android:layout_width="300dp"  android:layout_height="300dp"  android:id="@+id/imageView"  android:scaleType="fitXY"  android:background="@mipmap/ic_launcher"  android:layout_marginTop="40dp"  android:layout_marginLeft="30dp"  /></LinearLayout>

效果圖：