[Android Study Notes] Android Studio Lesson 4 - CheckBox

package com.example.urien.secondapp;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.Toast;

public class Lesson4_Activity extends AppCompatActivity {

    //1. Declare the control
    private CheckBox L4_checkBoxeat;
    private CheckBox L4_checkBoxsleep;
    private CheckBox L4_checkBoxstudy;
    private CheckBox L4_checkBoxAll;
    private Button L4_bt_confim;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate (savedInstanceState);
        setContentView(R.layout.activity_lesson4_);

        //2. Find the control
        L4_checkBoxeat = findViewById(R.id.L4_checkBoxeat);
        L4_checkBoxstudy = findViewById(R.id.L4_checkBoxstudy);
        L4_checkBoxsleep = findViewById(R.id.L4_checkBoxsleep);
        L4_checkBoxAll = findViewById(R.id.L4_checkBoxAll);
        L4_bt_confim = findViewById(R.id.L4_bt_confim);

        //set the listener
        setListener();
    }

    //4. Set the click listener
    private void setListener(){
        Onclick onclick = new Onclick();
        L4_checkBoxeat.setOnClickListener(onclick);
        L4_checkBoxsleep.setOnClickListener(onclick);
        L4_checkBoxstudy.setOnClickListener(onclick);
        L4_checkBoxAll.setOnClickListener(onclick);
        L4_bt_confim.setOnClickListener(onclick);

    }

    //3. Implement the listener interface
    class Onclick implements View.OnClickListener{
        @Override
        public void onClick(View v) {
            String str = null;
            switch (v.getId()){
                case R.id.L4_checkBoxeat:
                    str = "eat";
                    break;
                case R.id.L4_checkBoxsleep:
                    str = "sleep";
                    break;
                case R.id.L4_checkBoxstudy:
                    str = "learn";
                    break;
                case R.id.L4_checkBoxAll:
                    if(L4_checkBoxAll.isChecked()){
                        L4_checkBoxeat.setChecked(true);
                        L4_checkBoxsleep.setChecked(true);
                        L4_checkBoxstudy.setChecked(true);
                    }
                    else{
                        L4_checkBoxeat.setChecked(false);
                        L4_checkBoxsleep.setChecked(false);
                        L4_checkBoxstudy.setChecked(false);
                    }
                case R.id.L4_bt_confim:
                    if(L4_checkBoxeat.isChecked())  str = "吃饭";
                    if(L4_checkBoxsleep.isChecked()) str += " 睡觉";
                    if(L4_checkBoxstudy.isChecked()) str += " 学习";
                    break;
            }
            if(v.getId() != R.id.L4_checkBoxAll)
                Toast.makeText(Lesson4_Activity.this,str,Toast.LENGTH_SHORT).show();
        }
    }
}

The above uses the click listener event, and then expands the full selection box to the state change listener event:

package com.example.urien.secondapp;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.Toast;

public class Lesson4_Activity extends AppCompatActivity {

    //1. Declare the control
    private CheckBox L4_checkBoxeat;
    private CheckBox L4_checkBoxsleep;
    private CheckBox L4_checkBoxstudy;
    private CheckBox L4_checkBoxAll;
    private Button L4_bt_confim;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate (savedInstanceState);
        setContentView(R.layout.activity_lesson4_);

        //2. Find the control
        L4_checkBoxeat = findViewById(R.id.L4_checkBoxeat);
        L4_checkBoxstudy = findViewById(R.id.L4_checkBoxstudy);
        L4_checkBoxsleep = findViewById(R.id.L4_checkBoxsleep);
        L4_checkBoxAll = findViewById(R.id.L4_checkBoxAll);
        L4_bt_confim = findViewById(R.id.L4_bt_confim);

        //set the listener
        setListener();
    }

    //4. Set the listener
    private void setListener(){
        Onclick onclick = new Onclick();
        checkBoxChangeListener changeListener = new checkBoxChangeListener();

        L4_bt_confim.setOnClickListener(onclick);
        L4_checkBoxeat.setOnCheckedChangeListener(changeListener);
        L4_checkBoxsleep.setOnCheckedChangeListener(changeListener);
        L4_checkBoxstudy.setOnCheckedChangeListener(changeListener);
        L4_checkBoxAll.setOnCheckedChangeListener(changeListener);
    }

    //3. Implement the click event listener interface
    class Onclick implements View.OnClickListener{

        @Override
        public void onClick(View v) {
            String str = "";
            if(L4_checkBoxeat.isChecked())  str = "吃饭";
            if(L4_checkBoxsleep.isChecked())    str += " 睡觉";
            if(L4_checkBoxstudy.isChecked())    str += " 学习";
            Toast.makeText(Lesson4_Activity.this,str,Toast.LENGTH_LONG).show();
        }
    }
    //3. Implement CheckBox change event listener interface
    class checkBoxChangeListener implements CompoundButton.OnCheckedChangeListener{

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            String str = null;
            switch (buttonView.getId()){
                case R.id.L4_checkBoxeat:
                    if(isChecked) str = "吃饭";
                    break;
                case R.id.L4_checkBoxsleep:
                    if(isChecked)   str = "睡觉";
                    break;
                case R.id.L4_checkBoxstudy:
                    if(isChecked)   str = "学习";
                    break;
                case R.id.L4_checkBoxAll:
                    if(isChecked){
                        L4_checkBoxeat.setChecked(true);
                        L4_checkBoxsleep.setChecked(true);
                        L4_checkBoxstudy.setChecked(true);
                        str = "Eat, sleep and study";
                    }
                    else{
                        L4_checkBoxeat.setChecked(false);
                        L4_checkBoxsleep.setChecked(false);
                        L4_checkBoxstudy.setChecked(false);
                    }
                    break;
            }
            if(isChecked)
                Toast.makeText(Lesson4_Activity.this,str,Toast.LENGTH_SHORT).show();
        }
    }
}

By Urien May 7, 2018 17:16:25