Adv

Android LongClick Event

The concept here is the long click event  in any widget in any android. For example long click events in:

  1. ListView
  2. GridView
  3. RecyclerView

 

Feel free to post any example.

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1 Example

  1. Android Custom ListView – LongClick Events

    This is an android tutorial to explore how to handle longclick events in a custom listview with images and text.

    Let’s go.

    1. Create Basic Activity Project

    1. First create a new project in android studio. Go to File –> New Project.
    2. Type the application name and choose the company name.
    3. Choose minimum SDK.
    4. Choose Basic activity.
    5. Click Finish.

    Basic activity will have a toolbar and floating action button already added in the layout

    Normally two layouts get generated with this option:

    No. Name Type Description
    1. activity_main.xml XML Layout Will get inflated into MainActivity Layout.Typically contains appbarlayout with toolbar.Also has a floatingactionbutton.
    2. content_main.xml XML Layout Will be included into activity_main.xml.You add your views and widgets here.
    3. MainActivity.java Class Main Activity.

    In this example I used a basic activity.

    The activity will automatically be registered in the android_manifest.xml. Android Activities are components and normally need to be registered as an application component.

    If you’ve created yours manually then register it inside the <application>...<application> as following, replacing the MainActivity with your activity name:

            <activity android_name=".MainActivity">
    
                <intent-filter>
    
                    <action android_name="android.intent.action.MAIN" />
    
                    <category android_name="android.intent.category.LAUNCHER" />
    
                </intent-filter>
    
            </activity>
    

    You can see that one action and category are specified as intent filters. The category makes our MainActivity as launcher activity. Launcher activities get executed first when th android app is run.

    Advantage of Creating Basic Activity project

    You can optionally choose empty activity over basic activity for this project.

    However basic activity has the following advantages:

    No. Advantage
    1. Provides us a readymade toolbar which gives us actionbar features yet easily customizable
    2. Provides us with appbar layout which implements material design appbar concepts.
    3. Provides a FloatinActionButton which we can readily use to initiate quick actions especially in examples like these.
    4. Decouples our custom content views and widgets from the templating features like toolbar.

    Generated Project Structure

    AndroidStudio will generate for you a project with default configurations via a set of files and directories.

    Here are the most important of them:

    No. File Major Responsibility
    1. build/ A directory containing resources that have been compiled from the building of application and the classes generated by android tools. Such a tool is the R.java file. R.java file normally holds the references to application resources.
    2. libs/ To hold libraries we use in our project.
    3. src/main/ To hold the source code of our application.This is the main folder you work with.
    4. src/main/java/ Contains our java classes organized as packages.
    5. src/main/res/ Contains our project resources folders as follows.
    6. src/main/res/drawable/ Contains our drawable resources.
    7. src/main/res/layout/ Contains our layout resources.
    8. src/main/res/menu/ Contains our menu resources XML code.
    9. src/main/res/values/ Contains our values resources XML code.These define sets of name-value pairs and can be strings, styles and colors.
    10. AndroidManifest.xml This file gets autogenerated when we create an android project.It will define basic information needed by the android system like application name,package name,permissions,activities,intents etc.
    11. build.gradle Gradle Script used to build the android app.

    2. Dependencies

    We really have no external dependencies. Instead we simply specify a couple of support library dependencies.

    dependencies {
        compile fileTree(dir: 'libs', include: ['*.jar'])
        testCompile 'junit:junit:4.12'
        compile 'com.android.support:appcompat-v7:23.2.1'
        compile 'com.android.support:design:23.2.1'
        compile 'com.android.support:cardview-v7:23.2.1'
    }

    3. Create User Interface

    User interfaces are typically created in android using XML layouts as opposed by direct java coding.

    This is an example fo declarative programming.

    Advantages of Using XML over Java

    No. Advantage
    1. Declarative creation of widgets and views allows us to use a declarative language XML which makes is easier.
    2. It’s easily maintanable as the user interface is decoupled from your Java logic.
    3. It’s easier to share or download code and safely test them before runtime.
    4. You can use XML generated tools to generate XML

    Here are our layouts for this project:

    (a). activity_main.xml
    • This layout gets inflated to MainActivity user interface.
    • It includes the content_main.xml.

    Here are some of the widgets, views and viewgroups that get employed”

    No. View/ViewGroup Package Role
    1. CordinatorLayout android.support.design.widget Super-powered framelayout that provides our application’s top level decoration and is also specifies interactions and behavioros of all it’s children.
    2. AppBarLayout android.support.design.widget A LinearLayout child that arranges its children vertically and provides material design app bar concepts like scrolling gestures.
    3. ToolBar <android.support.v7.widget A ViewGroup that can provide actionbar features yet still be used within application layouts.
    4. FloatingActionButton android.support.design.widget An circular imageview floating above the UI that we can use as buttons.
    <?xml version="1.0" encoding="utf-8"?>
    <android.support.design.widget.CoordinatorLayout 
        
        
        android_layout_width="match_parent"
        android_layout_height="match_parent"
        android_fitsSystemWindows="true"
        tools_context="com.tutorials.hp.listviewlongclick.MainActivity">
    
        <android.support.design.widget.AppBarLayout
            android_layout_width="match_parent"
            android_layout_height="wrap_content"
            android_theme="@style/AppTheme.AppBarOverlay">
    
            <android.support.v7.widget.Toolbar
                android_id="@+id/toolbar"
                android_layout_width="match_parent"
                android_layout_height="?attr/actionBarSize"
                android_background="?attr/colorPrimary"
                app_popupTheme="@style/AppTheme.PopupOverlay" />
    
        </android.support.design.widget.AppBarLayout>
    
        <include layout="@layout/content_main" />
    
        <android.support.design.widget.FloatingActionButton
            android_id="@+id/fab"
            android_layout_width="wrap_content"
            android_layout_height="wrap_content"
            android_layout_gravity="bottom|end"
            android_layout_margin="@dimen/fab_margin"
            android_src="@android:drawable/ic_dialog_email" />
    
    </android.support.design.widget.CoordinatorLayout>
    
    (b). content_main.xml

    Let’s add our ListView here.

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout 
        
        
        android_layout_width="match_parent"
        android_layout_height="match_parent"
        android_paddingBottom="@dimen/activity_vertical_margin"
        android_paddingLeft="@dimen/activity_horizontal_margin"
        android_paddingRight="@dimen/activity_horizontal_margin"
        android_paddingTop="@dimen/activity_vertical_margin"
        app_layout_behavior="@string/appbar_scrolling_view_behavior"
        tools_context="com.tutorials.hp.listviewlongclick.MainActivity"
        tools_showIn="@layout/activity_main">
    
        <ListView
            android_layout_width="wrap_content"
            android_layout_height="wrap_content"
            android_id="@+id/lv"
            android_layout_alignParentLeft="true"
            android_layout_alignParentStart="true" />
    </RelativeLayout>
    
    (c). model.xml

    This layout will define the custom row model for our ListView.

    In this case our ListView will have images and text.

    <?xml version="1.0" encoding="utf-8"?>
    <android.support.v7.widget.CardView 
        android_orientation="horizontal" android_layout_width="match_parent"
        
        android_layout_margin="10dp"
        card_view_cardCornerRadius="10dp"
        card_view_cardElevation="10dp"
    
        android_layout_height="wrap_content">
    
        <RelativeLayout
            android_layout_width="match_parent"
            android_layout_height="match_parent">
    
            <ImageView
                android_layout_width="wrap_content"
                android_layout_height="wrap_content"
                android_id="@+id/movieImage"
                android_padding="10dp"
                android_src="@drawable/ghost" />
    
            <TextView
                android_layout_width="wrap_content"
                android_layout_height="wrap_content"
                android_textAppearance="?android:attr/textAppearanceLarge"
                android_text="Name"
                android_id="@+id/nameTxt"
                android_padding="10dp"
                android_textColor="@color/colorAccent"
                android_layout_below="@+id/movieImage"
                android_layout_alignParentLeft="true"
                 />
    
            <TextView
                android_layout_width="wrap_content"
                android_layout_height="wrap_content"
                android_textAppearance="?android:attr/textAppearanceLarge"
                android_text=" John Doe a former FBI Agent and now Physics teacher .is wrongly accussed of murdering an innocent child.He makes it his business to find the bad guys who did taht.He convinces hacker Aram to join him.....
                "
                android_id="@+id/descTxt"
                android_padding="10dp"
                android_layout_below="@+id/nameTxt"
                android_layout_alignParentLeft="true"
                />
    
            <TextView
                android_layout_width="wrap_content"
                android_layout_height="wrap_content"
                android_textAppearance="?android:attr/textAppearanceMedium"
                android_text="TV Show"
                android_id="@+id/posTxt"
                android_padding="10dp"
    
                android_layout_below="@+id/movieImage"
                android_layout_alignParentRight="true" />
    
            <CheckBox
                android_layout_width="wrap_content"
                android_layout_height="wrap_content"
                android_id="@+id/chk"
                android_layout_alignParentRight="true"
                />
    
        </RelativeLayout>
    </android.support.v7.widget.CardView>

    Let’s now come to our Java classes:

    4. Movie.java

    Our data object.

    package com.tutorials.hp.listviewlongclick;
    
    public class Movie {
    
        private String name;
        private int image;
    
        public Movie(String name, int image) {
            this.name = name;
            this.image = image;
        }
    
        public String getName() {
            return name;
        }
    
        public int getImage() {
            return image;
        }
    }
    

    5. ItemLongClickListener.java

    Our long click listener interface.

    package com.tutorials.hp.listviewlongclick;
    
    import android.view.View;
    
    public interface ItemLongClickListener {
    
        void onLongItemClick(View v);
    
    }
    

    6. MyViewHolder.java

    Will hold our widgets to be recycled.

    package com.tutorials.hp.listviewlongclick;
    
    import android.view.View;
    import android.widget.ImageView;
    import android.widget.TextView;
    
    public class MyViewHolder implements View.OnLongClickListener {
    
        ImageView img;
        TextView nameTxt;
        ItemLongClickListener itemLongClickListener;
    
        public MyViewHolder(View v) {
            img= (ImageView) v.findViewById(R.id.movieImage);
            nameTxt= (TextView) v.findViewById(R.id.nameTxt);
    
            v.setOnLongClickListener(this);
    
        }
    
        public void setItemLongClickListener(ItemLongClickListener ic)
        {
            this.itemLongClickListener=ic;
        }
    
        @Override
        public boolean onLongClick(View v) {
            this.itemLongClickListener.onLongItemClick(v);
            return false;
        }
    }
    

    7. CustomAdapter.java

    Will inflate our model.xml and bind data to resultant views.

    package com.tutorials.hp.listviewlongclick;
    
    import android.content.Context;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.Toast;
    
    import java.util.ArrayList;
    
    public class CustomAdapter extends BaseAdapter {
    
        Context c;
        ArrayList<Movie> movies;
        LayoutInflater inflater;
    
        public CustomAdapter(Context c, ArrayList<Movie> movies) {
            this.c = c;
            this.movies = movies;
        }
    
        @Override
        public int getCount() {
            return movies.size();
        }
    
        @Override
        public Object getItem(int position) {
            return movies.get(position);
        }
    
        @Override
        public long getItemId(int position) {
            return position;
        }
    
        //SHALL RETURN A ROW
        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {
    
            if(inflater==null)
            {
                inflater= (LayoutInflater) c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            }
    
            //CONVERT FROM XML TO JAVA
            if(convertView==null)
            {
                convertView=inflater.inflate(R.layout.model,parent,false);
            }
    
            //BIND DATA TO VIEWS
            MyViewHolder holder=new MyViewHolder(convertView);
            holder.nameTxt.setText(movies.get(position).getName());
            holder.img.setImageResource(movies.get(position).getImage());
    
            holder.setItemLongClickListener(new ItemLongClickListener() {
                @Override
                public void onLongItemClick(View v) {
                    Toast.makeText(c,movies.get(position).getName(),Toast.LENGTH_SHORT).show();
                }
            });
    
            return convertView;
        }
    }
    

    8. MainActivity.java

    Our Main activity.

    package com.tutorials.hp.listviewlongclick;
    
    import android.os.Bundle;
    import android.support.design.widget.FloatingActionButton;
    import android.support.design.widget.Snackbar;
    import android.support.v7.app.AppCompatActivity;
    import android.support.v7.widget.RecyclerView;
    import android.support.v7.widget.Toolbar;
    import android.view.View;
    
    import android.widget.ListView;
    
    import java.util.ArrayList;
    
    public class MainActivity extends AppCompatActivity {
    
        ListView lv;
        CustomAdapter adapter;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
            setSupportActionBar(toolbar);
    
            FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
            fab.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                            .setAction("Action", null).show();
                }
            });
    
            lv= (ListView) findViewById(R.id.lv);
            adapter=new CustomAdapter(this,getMovies());
    
            //SET ADAPTER
            lv.setAdapter(adapter);
    
        }
    
        private ArrayList<Movie> getMovies() {
    
            //COLECTION OF CRIME MOVIES
            ArrayList<Movie> movies=new ArrayList<>();
    
            Movie movie=new Movie("Shuttle Carrier",R.drawable.shuttlecarrier);
    
            //ADD ITR TO COLLECTION
            movies.add(movie);
    
            movie=new Movie("Fruts",R.drawable.fruits);
            movies.add(movie);
    
            movie=new Movie("Breaking Bad",R.drawable.breaking);
            movies.add(movie);
    
            movie=new Movie("Crisis",R.drawable.crisis);
            movies.add(movie);
    
            movie=new Movie("Ghost Rider",R.drawable.rider);
            movies.add(movie);
    
            movie=new Movie("Star Wars",R.drawable.starwars);
            movies.add(movie);
    
            movie=new Movie("BlackList",R.drawable.red);
            movies.add(movie);
    
            movie=new Movie("Men In Black",R.drawable.meninblack);
            movies.add(movie);
    
            movie=new Movie("Game Of Thrones",R.drawable.thrones);
            movies.add(movie);
    
            return movies;
        }
    
    }
    

    Download Code

     

    Resource Link
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    [/sociallocker]

    Best Regards,
    Oclemy.




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