第五第六周作业

1.返回键实现对话框弹出是否退出应用程序

import android.content.DialogInterface;
import android.os.Bundle;
 
public class Main6Activity extends AppCompatActivity {
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main6);
 
    }
 
    @Override
    public void onBackPressed() {
        final AlertDialog dialog;
        AlertDialog.Builder builder=new AlertDialog.Builder(this)
                .setTitle("普通对话框")//设置对话框标题
                .setIcon(R.mipmap.ic_launcher)//设置设置标题图标
                .setMessage("是否确定退出应用：")//设置对话框的提示信息
                //添加"确定"按钮
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int i) {
                        dialog.dismiss();//关闭对话框
                        Main6Activity.this.finish();//关闭MainActivity
                    }
                })
                //t添加"取消"按钮
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int i) {
                        dialog.dismiss();
                    }
                });
        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）

import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private String[] sexArry={"男","女"};
    private int sex=0;
    private TextView textView;

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

        findViewById(R.id.bt).setOnClickListener(this);
    }


    @Override
    public void onClick(View view) {
        AlertDialog dialog;
        AlertDialog.Builder builder=new AlertDialog.Builder(this)
                .setTitle("选择你的性别")
                .setSingleChoiceItems(new String[]{"男", "女"},sex, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int i) {
                        sex=i;
                    }
                })
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int i) {
                        dialog.dismiss();
                        if (sex==0){
                            Toast.makeText(MainActivity.this, "你选择的性别是男", Toast.LENGTH_SHORT).show();
                        }else{
                            Toast.makeText(MainActivity.this, "你选择的性别是女", Toast.LENGTH_SHORT).show();
                        }

                    }
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int i) {
                        dialog.dismiss();
                    }
                });

        dialog=builder.create();
        dialog.show();

    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical">

    <Button
        android:id="@+id/bt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="按钮"
        android:textSize="50dp"
        android:layout_gravity="center"
        android:layout_marginTop="200dp"
        />


</LinearLayout>

 

 3.布局(详见:Android第五周上机word文档)

<?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=".Main7Activity"
    android:background="#4CAF50">
    <TextView
        android:id="@+id/t_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="1.TixtView显示文本信息"
        android:textSize="25dp"
        android:textColor="#F81F1F"
        android:gravity="center"/>
    <Button
        android:id="@+id/bt1"
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:text="2.按钮"
        android:textSize="25dp"
        android:textColor="#F81F1F"
        android:layout_below="@id/t_1"
        android:layout_centerHorizontal="true"/>
    <EditText
        android:id="@+id/e1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/bt1"
        android:hint="输入信息"
        android:maxLines="2"
        android:textSize="25dp"/>
    <RadioButton
        android:id="@+id/rbtn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="25dp"
        android:text="男"
        android:layout_below="@id/e1"/>
    <RadioButton
        android:id="@+id/rbtn2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="25dp"
        android:text="女"
        android:layout_toRightOf="@id/rbtn1"
        android:layout_below="@id/e1"
        android:layout_marginLeft="5dp"/>
    <CheckBox
        android:id="@+id/cb1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/rbtn1"
        android:text="电脑"
        android:textSize="25dp"/>
    <CheckBox
        android:id="@+id/cb2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/cb1"
        android:text="手机"
        android:textSize="25dp"/>
</RelativeLayout>