ASD五六周

1.返回键实现对话框弹出是否退出应用程序

public class MainActivity extends Activity {

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

    }
    public void onBackPressed() {
        // TODO Auto-generated method stub
        AlertDialog.Builder builder=new AlertDialog.Builder(this)
                .setTitle("普通对话框")
                .setMessage("是否退出至主菜单")
                .setIcon(R.drawable.ic_launcher_background)
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {

                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        dialog.dismiss();
                        MainActivity.this.finish();
                    }
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {

                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        dialog.dismiss();
                    }
                });
        AlertDialog dialog=builder.create();
        dialog.show();
    }

 

2.实现以下场景：从一个activity中点击一个按钮后，弹出一个单选按钮对话框，上面有“男”“女”两个选项，选定后，TOAST弹出 你选择了男，或你选择了女（参考书上改字体）

public class MainActivity extends Activity implements OnClickListener {

    private int num=0;
    private int num1[]={0,1};
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.bt).setOnClickListener(this);
    }
    public void onClick(View v) {
        // TODO Auto-generated method stub
        AlertDialog.Builder builder=new AlertDialog.Builder(this)
                .setTitle("性别")
                .setSingleChoiceItems(new String[]{"男","女"}, -1, new DialogInterface.OnClickListener() {

                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        num=which;
                    }
                })
                .setPositiveButton("确定",new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        if(num==0){
                            Toast.makeText(MainActivity.this, "你选择的是男", Toast.LENGTH_LONG).show();
                        }else{
                            Toast.makeText(MainActivity.this, "你选择的是女", Toast.LENGTH_SHORT).show();
                        }
                        dialog.dismiss();
                    }
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {

                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        dialog.dismiss();
                    }
                });
        AlertDialog dialog=builder.create();
        dialog.show();
    }

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

   <Button
        android:id="@+id/bt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="请选择你的性别"

        />

</RelativeLayout>

 

3.布局(详见:Android第五周上机word文档)

 

4.教材p76页 图3—17购物商城界面