android拍照保存全尺寸圖片

這種保存圖片的好處：在有限的內存下，管理許多全尺寸的圖片會很棘手。如果發現應用在展示了少量圖片後消耗了所有內存，我們可以通過縮放圖片到目標視圖尺寸，之後再載入到內存中的方法，來顯著降低內存的使用。

demo已解決的問題：在onCreate()得到控件的寬度和長度，

在onCreate()方法中調用

ViewTreeObserver vto = image.getViewTreeObserver();

vto.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
    public boolean onPreDraw() {
        targetH = image.getMeasuredHeight();
        targetW = image.getMeasuredWidth();

        return true;
    }
});

如果希望照片對我們的應用而言是私有的，那麼可以使用getExternalFilesDir()提供的目錄

如果希望照片對所有應用共享，那麼可以使用getExternalStoragePublicDirectory()提供的目錄

首先加一個寫的權限

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

按鈕點擊

button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        //判斷是否有相機
        if (intent.resolveActivity(getPackageManager()) != null) {
            File photoFIle=null;
            try {
                photoFIle = createImageFile();
            } catch (Exception e) {
                e.printStackTrace();
            }
            if (photoFIle != null) {
                //怎麼將拍好的照片保存在sd卡中？
               /*
               首先在sd卡中創建一個空的.jpg文件，然後獲取創建好的.jpg的uri,
               接着通過intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFIle));
               MediaStore.EXTRA_OUTPUT這個表示照相完成後保存圖片在uri這個.jpg文件中
                */
                intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFIle));
                gallerAddPic();
                startActivityForResult(intent,REQUEST_IMAGES);
            }

        }
    }
});

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_IMAGES && resultCode == RESULT_OK) {

        setPic();
     /*   Bundle bundle=data.getExtras();
        Bitmap bitmap = (Bitmap) bundle.get("data");
        image.setImageBitmap(bitmap);*/

    }
}

private void setPic(){
    Log.d("test", targetH+";;;");
    BitmapFactory.Options bmOptions=new BitmapFactory.Options();
    bmOptions.inJustDecodeBounds=true;//設置inJustDecodeBounds爲true後，decodeFile並不分配空間，但可計算出原始圖片的長度和寬度
    //bmOptions指向mCurrentPhotoPaht路徑中的圖片
    BitmapFactory.decodeFile(mCurrentPhotoPaht, bmOptions);

    //之所以phtotW=0是因爲mCurrentPhotoPaht的路徑出錯，找不到拍照後保存下的圖片
    float photoW=bmOptions.outHeight;
    float photoH=bmOptions.outHeight;
    Log.d("test", "photoW" + photoW);
    float scaleFactor = Math.min(photoW / targetW, photoH / targetH);//設置縮放比例
    bmOptions.inJustDecodeBounds=false;//
    bmOptions.inSampleSize=(int) scaleFactor;

    bmOptions.inPurgeable=true;//inPurgeable:設置爲True時,表示系統內存不足時可以被回 收
    Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPaht, bmOptions);
    image.setImageBitmap(bitmap);
}
//觸發系統的Media Scanner，將我們的照片添加到Media Provider的數據庫中，就是將照片添加到相冊，拍照後你就可以在相冊中看到
private void gallerAddPic(){
    Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
    Log.d("test", mCurrentPhotoPaht + ":gallerAddPic");
    File f = new File(mCurrentPhotoPaht);
    Uri contentUri = Uri.fromFile(f);
    mediaScanIntent.setData(contentUri);
    this.sendBroadcast(mediaScanIntent);
}
private File createImageFile() throws IOException{
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(imageFileName, ".jpg", storageDir);
    mCurrentPhotoPaht=image.getAbsolutePath();
    Log.d("test", mCurrentPhotoPaht);
    return image;
}

//保存路徑長度，寬度，防止重建Activity時長度，寬度，mCureentPhotoPaht出錯

@Override
protected void onSaveInstanceState(Bundle outState) {
    outState.putString("path",mCurrentPhotoPaht);
    outState.putInt("w",targetW);
    outState.putInt("h",targetH);
    Log.d("test", "onSaveInstance"+mCurrentPhotoPaht);
    super.onSaveInstanceState(outState);
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    mCurrentPhotoPaht = savedInstanceState.getString("path");

    targetH = savedInstanceState.getInt("h");
    targetW = savedInstanceState.getInt("w");
    Log.d("test", "onresotre:" + mCurrentPhotoPaht);
    super.onRestoreInstanceState(savedInstanceState);
}