Android开发中bitmap的优化
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/hello" /> <ImageView android:id="@+id/imageview" android:layout_gravity="center" android:layout_width="fill_parent" android:layout_height="fill_parent" android:scaleType="center" /> </LinearLayout> java源码 import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.widget.ImageView; import android.widget.Toast; public class AndroidImage extends Activity { private String imageFile = "/sdcard/AndroidSharedPreferencesEditor.png"; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); ImageView myImageView = (ImageView)findViewById(R.id.imageview); //Bitmap bitmap = BitmapFactory.decodeFile(imageFile); //myImageView.setImageBitmap(bitmap); Bitmap bitmap; float imagew = 300; float imageh = 300; BitmapFactory.Options bitmapFactoryOptions = new BitmapFactory.Options(); bitmapFactoryOptions.inJustDecodeBounds = true; bitmap = BitmapFactory.decodeFile(imageFile, bitmapFactoryOptions); int yRatio = (int)Math.ceil(bitmapFactoryOptions.outHeight/imageh); int xRatio = (int)Math.ceil(bitmapFactoryOptions.outWidth/imagew); if (yRatio > 1 || xRatio > 1){ if (yRatio > xRatio) { bitmapFactoryOptions.inSampleSize = yRatio; Toast.makeText(this, "yRatio = " + String.valueOf(yRatio), Toast.LENGTH_LONG).show(); } else { bitmapFactoryOptions.inSampleSize = xRatio; Toast.makeText(this, "xRatio = " + String.valueOf(xRatio), Toast.LENGTH_LONG).show(); } } else{ Toast.makeText(this, "inSampleSize = 1", Toast.LENGTH_LONG).show(); } bitmapFactoryOptions.inJustDecodeBounds = false; bitmap = BitmapFactory.decodeFile(imageFile, bitmapFactoryOptions); myImageView.setImageBitmap(bitmap); } }
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