Things every android developer should know - part 4

Description: In this post, I will show you some interesting tools from Android Studio that developers use.

Also check out Part 1,Part 2  and  Part 3.


So let's get started.

1. Layout Inspector: Layout Inspector is an interesting tool to help track view and their respective properties. It contains-

•    View Tree - contains the hierarchy of the Android widgets displaying the full nesting of views.
•    Properties Table - contains the properties attached to the respective view. e.g.: layouts/methods/padding and many more.

 a) How to enable it?

        Goto Tools -> Android -> Layout Inspector fig.1 

     

fig.1 Layout Inspector

 Note: Make sure you have an Android process running for your app and you have an active window present to take the screenshot.

 b) How to understand it?(fig.2)

    Left
       - 'View Tree' showing the full hierarchy of the screen.
   Center
     - Screenshot of the active window       
   Right
      - 'Properties Table' for each view.

  View Click
    - Properties of the widgets get updated on the right pane i.e. 'Properties Table.' and get highlighted on the screenshot screen.

fig.2 Layout Inspector

fig.3 Layout Inspector with Properties

RecyclerView:

<RelativeLayout 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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">
    <android.support.v7.widget.RecyclerView
        android:id="@+id/percentList"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />
</RelativeLayout>

RecyclerView Item:

<android.support.percent.PercentRelativeLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:id="@+id/fifty_huntv"
        android:background="#ff7acfff"
        android:text="20% - 50%"
        android:textColor="@android:color/white"
        style="@style/STYLE_PERCENT_TV"
        app:layout_heightPercent="20%"
        app:layout_widthPercent="50%" />
    <TextView
        android:layout_toRightOf="@id/fifty_huntv"
        android:background="#ffff5566"
        android:text="80%-50%"
        style="@style/STYLE_PERCENT_TV"
        app:layout_heightPercent="80%"
        app:layout_widthPercent="50%" />


</android.support.percent.PercentRelativeLayout>

Its an amazing tool to analyse the screen UI for the developers with all the information available on single click. Simply great.

2. How to change the DPI of the Phone using ADB?

Many times in our development phase we want to check the look of Android UI on low/high-end devices. Changing the DPI could come in handy in such cases.

So let get started.

Step 1: Find out your phone's dpi using the below command of adb shell. Search for 'mBaseDisplayInfo='. And then search for density within it. Save it for the future to revert our DPI

adb shell dumpsys display

Step 2: Search for 'mBaseDisplayInfo' and 'density' as shown in fig.4

fig.4 Display Density

Step 3: Finally enter below adb command to change the dpi. (fig.5) with 200dpi,420dpi and 600dpi respectively

adb shell wm density 150

 


Note: If the changes do not reflect you can also try:

adb shell wm density 150 && adb reboot

That it, the screen will be reloaded and icon sizes will change to withstand the density specified in the command.

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Android Multiple row layout using RecyclerView

Description: In this post I'm gonna show you how we can have multiple row layout in Android's Material Design  RecyclerView  using   getItemViewType.

compile 'com.android.support:cardview-v7:23.0.0'
compile 'com.android.support:recyclerview-v7:23.0.0'

GitHub Project HERE

So lets get started :-)

Step 1: Create Recycler Adapter by overriding getItemViewType method and giving the type for different layout as shown below.

@Override

public int getItemViewType(int position) {

    MultipleRowModel multipleRowModel = multipleRowModelList.get(position);

    if (multipleRowModel != null)
        return multipleRowMod.type;

    return super.getItemViewType(position);
}

Step 2: Create a viewHolder as per viewType .  We can create different row layout using viewType .

Note: viewType in onCreateviewholder is retured from getItemViewType in Step 1.

@Override
public MultipleRowViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

    View view = null;

    if (viewType == AppConstant.FIRST_ROW)
        view = inflater.inflate(R.layout.view_row_first, parent, false);
    else if (viewType == AppConstant.OTHER_ROW)
        view = inflater.inflate(R.layout.view_row_other, parent, false);

    return new MultipleRowViewHolder(view, viewType);
}

Step 3: Lets integrated all this in one RecyclerView adapter.

public class MultipleRowAdapter extends RecyclerView.Adapter<MultipleRowViewHolder> {

    private LayoutInflater inflater = null;
    private List<MultipleRowModel> multipleRowModelList;

    public MultipleRowAdapter(Context context, List<MultipleRowModel> multipleRowModelList){
        this.multipleRowModelList = multipleRowModelList;
        inflater = LayoutInflater.from(context);
    }

    @Override
    public MultipleRowViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View view = null;

        if (viewType == AppConstant.FIRST_ROW)
            view = inflater.inflate(R.layout.view_row_first, parent, false);
        else if (viewType == AppConstant.OTHER_ROW)
            view = inflater.inflate(R.layout.view_row_other, parent, false);

        return new MultipleRowViewHolder(view, viewType);
    }

    @Override
    public void onBindViewHolder(MultipleRowViewHolder holder, int position) {
        holder.multipleContent.setText(multipleRowModelList.get(position).modelContent);
    }

    @Override
    public int getItemCount() {
        return (multipleRowModelList!= null && multipleRowModelList.size() > 0 ) ? multipleRowModelList.size() : 0;
    }

    @Override
    public int getItemViewType(int position) {

        MultipleRowModel multipleRowModel = multipleRowModelList.get(position);

        if (multipleRowModel != null)
            return multipleRowModel.type;

        return super.getItemViewType(position);
    }

}

Step 4: Finally our MainActivity looks something like this.

public class MainActivity extends AppCompatActivity {

    private RecyclerView multipleRowRecyclerView;
    private MultipleRowAdapter multipleRowAdapter;

    private List<MultipleRowModel> multipleRowModelList = new ArrayList<>();

    @Override

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

        multipleRowRecyclerView = (RecyclerView)findViewById(R.id.multipleRowRecyclerView);
        multipleRowRecyclerView.setHasFixedSize(true);

        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this, OrientationHelper.VERTICAL, false);
        multipleRowRecyclerView.setLayoutManager(linearLayoutManager);
        multipleRowRecyclerView.setItemAnimator(new DefaultItemAnimator());

        fillAdapter();

        multipleRowAdapter = new MultipleRowAdapter(MainActivity.this, multipleRowModelList);

        multipleRowRecyclerView.setAdapter(multipleRowAdapter);
    }

    private void fillAdapter() {

        int type;

        String content;

        for (int i = 0; i < 10; i++) {

            if (i == 0 || i == 5 || i == 9) {
                type = AppConstant.FIRST_ROW;
                content = "Type 1: This is Multiple row layout";
            } else {
                type = AppConstant.OTHER_ROW;
                content = "Type 2";
            }

            multipleRowModelList.add(new MultipleRowModel(type , content));
        }
    }
}

GitHub Project HERE

Sample Output :

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