1,點擊按鈕,指定action和uri,設定結果碼(ResultCode).到達手機默認相冊的Gallery.
代碼如下:
1. public void onClick(View v) {
2. // TODO Auto-generated method stub
3. Intent intent = new Intent(Intent.ACTION_PICK,
4. android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);//啟動照片Gallery
5. startActivityForResult(intent, 0);
6. }
2,選擇圖片,返回所選照片uri信息
代碼如下:
1. @Override
2. protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
3. // TODO Auto-generated method stub
4. super.onActivityResult(requestCode, resultCode, intent);
5.
6. if (resultCode == RESULT_OK) {//操作成功
7. Uri imgFileUri = intent.getData();//獲得所選照片的信息
3,處理圖片,設定合適的尺寸(正好適應屏幕)
設定BitmapFactory.Options 參數inJustDecodeBounds = true,即不創建bitmap,但可獲取bitmap的相關屬性。以寬高比例差距 最大者為基準。
代碼如下:
1. //由於返回的圖像可能太大而無法完全加載到內存中。系統有限制,需要處理。
2. Display currentDisplay = getWindowManager().getDefaultDisplay();
3. int defaultHeight = currentDisplay.getHeight();
4. int defaultWidth = currentDisplay.getWidth();
5.
6. BitmapFactory.Options bitmapFactoryOptions = new BitmapFactory.Options();
7. bitmapFactoryOptions.inJustDecodeBounds = true;///隻是為獲取原始圖片的尺寸,而不返回Bitmap對象
8. //註上:If set to true, the decoder will return null (no bitmap), but the out… fields will still be set,
9. //allowing the caller to query the bitmap without having to allocate the memory for its pixels
10. try {
11. Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imgFileUri), null, bitmapFactoryOptions);
12. int outHeight = bitmapFactoryOptions.outHeight;
13. int outWidth = bitmapFactoryOptions.outWidth;
14. int heightRatio = (int) Math.ceil((float)outHeight/defaultHeight);
15. int widthRatio = (int) Math.ceil((float)outWidth/defaultWidth);
16.
17. if (heightRatio > 1 || widthRatio >1) {
18. if (heightRatio > widthRatio) {
19. bitmapFactoryOptions.inSampleSize = heightRatio;
20. } else {
21. bitmapFactoryOptions.inSampleSize = widthRatio;
22. }
23. }
4,inJustDecodeBounds = false,創建將此bitmap賦給第一個ImageView。
代碼如下:
1. bitmapFactoryOptions.inJustDecodeBounds = false;
2. bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imgFileUri), null, bitmapFactoryOptions);
3.
4. mImageShow.setImageBitmap(bitmap);
5,繪制bitmap(選中的圖片),賦給第二個ImageView
代碼如下:
1. /*
2. * 在位圖上繪制位圖
3. */
4.
5. Bitmap bitmapAltered = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig());
6.
7. Canvas canvas = new Canvas(bitmapAltered);//bitmap提供瞭畫佈,隻在此提供瞭大小尺寸,偏移後並未有背景顯示出來
8.
9.
10. Paint paint = new Paint();
11.
12. canvas.drawBitmap(bitmap, 0, 0, paint);//繪制的圖片和之前的一模一樣
13.
14. mImageAltered.setImageBitmap(bitmapAltered);
摘自 小新專欄