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Implement custom LinearLayout for Gallery-like HorizontalScrollView

Last exercise explain the basic to "implement Gallery-like HorizontalScrollView". In this post, we are going to implement our custom LinearLayout for Gallery-like HorizontalScrollView.

MyHorizontalLayout.java, our custom LinearLayout for Gallery-like HorizontalScrollView.

package com.example.androidhorizontalscrollviewgallery; import java.util.ArrayList; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.util.AttributeSet; import android.widget.ImageView; import android.widget.LinearLayout; public class MyHorizontalLayout extends LinearLayout { Context myContext; ArrayList<String> itemList = new ArrayList<String>(); public MyHorizontalLayout(Context context) { super(context); myContext = context; } public MyHorizontalLayout(Context context, AttributeSet attrs) { super(context, attrs); myContext = context; } public MyHorizontalLayout(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); myContext = context; } void add(String path){ int newIdx = itemList.size(); itemList.add(path); addView(getImageView(newIdx)); } ImageView getImageView(int i){ Bitmap bm = null; if (i < itemList.size()){ bm = decodeSampledBitmapFromUri(itemList.get(i), 220, 220); } ImageView imageView = new ImageView(myContext); imageView.setLayoutParams(new LayoutParams(220, 220)); imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); imageView.setImageBitmap(bm); return imageView; } public Bitmap decodeSampledBitmapFromUri(String path, int reqWidth, int reqHeight) { Bitmap bm = null; // First decode with inJustDecodeBounds=true to check dimensions final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeFile(path, options); // Calculate inSampleSize options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; bm = BitmapFactory.decodeFile(path, options); return bm; } public int calculateInSampleSize( BitmapFactory.Options options, int reqWidth, int reqHeight) { // Raw height and width of image final int height = options.outHeight; final int width = options.outWidth; int inSampleSize = 1; if (height > reqHeight || width > reqWidth) { if (width > height) { inSampleSize = Math.round((float)height / (float)reqHeight); } else { inSampleSize = Math.round((float)width / (float)reqWidth); } } return inSampleSize; } }

Modify layout to include MyHorizontalLayout.

<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:orientation="vertical"> <HorizontalScrollView android:layout_width="match_parent" android:layout_height="wrap_content" > <com.example.androidhorizontalscrollviewgallery.MyHorizontalLayout android:id="@+id/mygallery" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" /> </HorizontalScrollView> </LinearLayout>

See how simple is the main code:

package com.example.androidhorizontalscrollviewgallery; import java.io.File; import android.os.Bundle; import android.os.Environment; import android.app.Activity; import android.widget.Toast; public class MainActivity extends Activity { MyHorizontalLayout myHorizontalLayout; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); myHorizontalLayout = (MyHorizontalLayout)findViewById(R.id.mygallery); String ExternalStorageDirectoryPath = Environment .getExternalStorageDirectory() .getAbsolutePath(); String targetPath = ExternalStorageDirectoryPath + "/test/"; Toast.makeText(getApplicationContext(), targetPath, Toast.LENGTH_LONG).show(); File targetDirector = new File(targetPath); File[] files = targetDirector.listFiles(); for (File file : files){ myHorizontalLayout.add(file.getAbsolutePath()); } } }