ch05.rar

package com.ehappy.excheckbox02; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.widget.CheckBox; import android.widget.CompoundButton; import android.widget.TextView; import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity { private TextView txtResult; private CheckBox chkBasketBall,chkFootBall,chkBaseBall; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // 取得介面元件的 id txtResult=(TextView) findViewById(R.id.txtResult); chkBasketBall = (CheckBox) findViewById(R.id.chkBasketBall); chkFootBall = (CheckBox) findViewById(R.id.chkFootBall); chkBaseBall = (CheckBox) findViewById(R.id.chkBaseBall); // 設定 CheckBox 元件 CheckedChange 事件的 listener 為 myListener chkBasketBall.setOnCheckedChangeListener(myListener); chkFootBall.setOnCheckedChangeListener(myListener); chkBaseBall.setOnCheckedChangeListener(myListener); } // 定義 onCheckedChanged 方法 private CheckBox.OnCheckedChangeListener myListener=new CheckBox.OnCheckedChangeListener(){ @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { int n=0; // 記錄共選了多少項 String sel=""; // 所有的選項結果 String s1="",s2="",s3=""; // 單一選項的結果 if(chkBasketBall.isChecked()){ n++; s1=chkBasketBall.getText().toString() + " "; }else{ s1=""; } if(chkFootBall.isChecked()){ n++; s2=chkFootBall.getText().toString() + " "; }else{ s2=""; } if(chkBaseBall.isChecked()){ n++; s3=chkBaseBall.getText().toString() + " "; }else{ s3=""; } sel=s1+s2+s3; txtResult.setText("最喜歡的球類有： " + sel + "共 " + n + " 項"); } }; }