Android checkbox和radiobutton 以及Toast和AlertDialog的使用

package com.example.radiobutton_01;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

public class MyActivity extends Activity {
private RadioGroup rg;
private Button btn;
/**
* Called when the activity is first created.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

rg = (RadioGroup)findViewById(R.id.rg);
btn = (Button)findViewById(R.id.btn);

btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
int len = rg.getChildCount();
String msg = "";
for(int i=0;i<len;i++) {
RadioButton rb = (RadioButton)rg.getChildAt(i);
if(rb.isChecked()) {
msg = rb.getText().toString();
break;
}
}

Toast.makeText(MyActivity.this,msg,Toast.LENGTH_SHORT).show();
}
});
}
}

package com.example.checkbox_01;

import android.app.Activity;
import android.app.AlertDialog;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.LinearLayout;

import java.util.ArrayList;
import java.util.List;

public class MyActivity extends Activity implements View.OnClickListener{
private List<CheckBox> checkBoxes = new ArrayList<CheckBox>();
/**
* Called when the activity is first created.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.main);

String[] checkBoxText = new String[]{
"are you student?","are you love android?","are you dev?"
};

LinearLayout linearLayout = (LinearLayout)getLayoutInflater().inflate(R.layout.main,null);

for(int i=0;i<checkBoxText.length;i++) {
CheckBox checkBox = (CheckBox)getLayoutInflater().inflate(R.layout.checkbox,null);
checkBox.setText(checkBoxText[i]);

checkBoxes.add(checkBox);
linearLayout.addView(checkBox,i);
}

setContentView(linearLayout);

Button btn = (Button)findViewById(R.id.btn);
btn.setOnClickListener(this);
}

@Override
public void onClick(View view) {
String s = "";
for(CheckBox cb : checkBoxes) {
if(cb.isChecked()) {
s+=cb.getText() + "\n";
}
}

if("".equals(s)) {
s = "你没有选择选项";
}

new AlertDialog.Builder(this).setMessage(s).setPositiveButton("关闭",null).show();
}
}