blog code snippet

access_attrs_demo.java

package com.vogella.android.view.compoundview;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class ColorOptionsView extends View {

  private View mValue;
  private ImageView mImage;

  public ColorOptionsView(Context context, AttributeSet attrs) {
    super(context, attrs);

    TypedArray a = context.obtainStyledAttributes(attrs,
        R.styleable.Options, 0, 0);
    String titleText = a.getString(R.styleable.Options_titleText);
    int valueColor = a.getColor(R.styleable.Options_valueColor,
        android.R.color.holo_blue_light);
    a.recycle();

    // more stuff
  }


} 

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="ColorOptionsView">
        <attr name="titleText" format="string" localization="suggested" />
        <attr name="valueColor" format="color" />
    </declare-styleable>
</resources> 

attrs_use_demo.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
<!-- define new name space for your attributes -->
    xmlns:custom="http://schemas.android.com/apk/res/com.vogella.android.view.compoundview"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
>
<!-- Assume that this is your new component. It uses your new attributes -->
        <com.vogella.android.view.compoundview.ColorOptionsView
            android:layout_width="match_parent"
            android:layout_height="?android:attr/listPreferredItemHeight"
            custom:titleText="Background color"
            custom:valueColor="@android:color/holo_green_light"
             />

</LinearLayout> 

ColorOptionsView.java

package com.vogella.android.customview.compoundview;

import com.vogella.android.view.compoundview.R;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class ColorOptionsView extends LinearLayout {

  private View mValue;
  private ImageView mImage;

  public ColorOptionsView(Context context, AttributeSet attrs) {
    super(context, attrs);

    TypedArray a = context.obtainStyledAttributes(attrs,
        R.styleable.ColorOptionsView, 0, 0);
    String titleText = a.getString(R.styleable.ColorOptionsView_titleText);
    int valueColor = a.getColor(R.styleable.ColorOptionsView_valueColor,
        android.R.color.holo_blue_light);
    a.recycle();

    setOrientation(LinearLayout.HORIZONTAL);
    setGravity(Gravity.CENTER_VERTICAL);

    LayoutInflater inflater = (LayoutInflater) context
        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    inflater.inflate(R.layout.view_color_options, this, true);

    TextView title = (TextView) getChildAt(0);
    title.setText(titleText);

    mValue = getChildAt(1);
    mValue.setBackgroundColor(valueColor);

    mImage = (ImageView) getChildAt(2);
  }

  public ColorOptionsView(Context context) {
    this(context, null);
  }

  public void setValueColor(int color) {
    mValue.setBackgroundColor(color);
  }

  public void setImageVisible(boolean visible) {
    mImage.setVisibility(visible ? View.VISIBLE : View.GONE);
  }

} 

compound_view_layout_layout_demo.xml

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android" >

    <TextView
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:layout_centerVertical="true"
      android:layout_marginLeft="16dp"
        android:textSize="18sp" 
        />

  <View
      android:layout_width="26dp"
      android:layout_height="26dp"
      android:layout_centerVertical="true"
      android:layout_marginLeft="16dp"
      android:layout_marginRight="16dp"
      />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
      android:layout_marginRight="16dp"
        android:layout_centerVertical="true" 
        android:visibility="gone"
        />
     
</merge> 

create_custom_view_attr_demo.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="Options">
        <attr name="titleText" format="string" localization="suggested" />
        <attr name="valueColor" format="color" />
    </declare-styleable>

</resources> 

custom_view_activity_layout_demo.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:custom="http://schemas.android.com/apk/res/com.vogella.android.view.compoundview"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:showDividers="middle"
    android:divider="?android:attr/listDivider"
    tools:context=".MainActivity" >

        <com.vogella.android.view.compoundview.ColorOptionsView
            android:id="@+id/view1"
            android:layout_width="match_parent"
            android:layout_height="?android:attr/listPreferredItemHeight"
            android:background="?android:selectableItemBackground"
            android:onClick="onClicked"
            custom:titleText="Background color"
            custom:valueColor="@android:color/holo_green_light"
             />

        <com.vogella.android.view.compoundview.ColorOptionsView
            android:id="@+id/view2"
            android:layout_width="match_parent"
            android:layout_height="?android:attr/listPreferredItemHeight"
            android:background="?android:selectableItemBackground"
            android:onClick="onClicked"
            custom:titleText="Foreground color"
            custom:valueColor="@android:color/holo_orange_dark"
             />

</LinearLayout> 

custom_view_demo_mainactivity.java

package com.vogella.android.customview.compoundview;

import com.vogella.android.view.compoundview.R;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
  }

  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
  }

  public void onClicked(View view) {
    String text = view.getId() == R.id.view1 ? "Background" : "Foreground";
    Toast.makeText(this, text, Toast.LENGTH_SHORT).show();
  }

} 

MyActivity.java

public class MyActivity extends Activity {

    private RetainedFragment dataFragment;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // find the retained fragment on activity restarts
        FragmentManager fm = getFragmentManager();
        dataFragment = (DataFragment) fm.findFragmentByTag(“data”);

        // create the fragment and data the first time
        if (dataFragment == null) {
            // add the fragment
            dataFragment = new DataFragment();
            fm.beginTransaction().add(dataFragment, “data”).commit();
            // load the data from the web
            dataFragment.setData(loadMyData());
        }

        // the data is available in dataFragment.getData()
        ...
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        // store the data in the fragment
        dataFragment.setData(collectMyLoadedData());
    }
}

MyRecyclerAdapter.java

public class MyRecyclerAdapter extends RecyclerView.Adapter<MyRecyclerAdapter.ViewHolder> {

    private List<ViewModel> items;
    private int itemLayout;

    public MyRecyclerAdapter(List<ViewModel> items, int itemLayout) {
        this.items = items;
        this.itemLayout = itemLayout;
    }

    @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(itemLayout, parent, false);
        return new ViewHolder(v);
    }

    @Override public void onBindViewHolder(ViewHolder holder, int position) {
        ViewModel item = items.get(position);
        holder.text.setText(item.getText());
        holder.image.setImageBitmap(null);
        Picasso.with(holder.image.getContext()).cancelRequest(holder.image);
        Picasso.with(holder.image.getContext()).load(item.getImage()).into(holder.image);
        holder.itemView.setTag(item);
    }

    @Override public int getItemCount() {
        return items.size();
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {
        public ImageView image;
        public TextView text;

        public ViewHolder(View itemView) {
            super(itemView);
            image = (ImageView) itemView.findViewById(R.id.image);
            text = (TextView) itemView.findViewById(R.id.text);
        }
    }
}

RecyclerView_remove_item.java

public void add(ViewModel item, int position) {
  items.add(position, item);
  notifyItemInserted(position);
}

public void remove(ViewModel item) {
  int position = items.indexOf(item);
  items.remove(position);
  notifyItemRemoved(position);
}

RetainedFragment.java

public class RetainedFragment extends Fragment {

    // data object we want to retain
    private MyDataObject data;

    // this method is only called once for this fragment
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // retain this fragment
        setRetainInstance(true);
    }

    public void setData(MyDataObject data) {
        this.data = data;
    }

    public MyDataObject getData() {
        return data;
    }
}

SamleHtml.html

<!doctype html>
<html lang="en">
<head>
    <meta charset="utf-8" />
    <title>Hello World</title>
 
    <!-- CSS for presentation. -->
    <style>
    h1 { font-size: 14px; color: hotpink; }
    button { color: red; }
    </style>
</head>
<body>
    <h1>Hello World</h1>
    <button>Click Me!</button>
 
    <!-- JavaScript for interactivity. -->
    <script>
 
    // Get a handle on the first button element in the document.
    var button = document.querySelector( "button" );
 
    // If a user clicks on it, say hello!
    button.addEventListener( "click", function( ev ) {
        alert( "Hello" );
    }, false);
 
    </script>
</body>
</html>