第五六周作业

1.返回键实现对话框弹出是否退出应用程序

 

 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）

<?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"
    android:orientation="vertical"
    tools:context=".Main3Activity">
    <TextView
        android:id="@+id/tv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="您的性别是："
        android:gravity="center"
        android:textSize="20sp"
        android:layout_marginTop="10dp"
        android:textColor="#FFFDB371"/>
    <Button
        android:id="@+id/bt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="选择性别"
        android:layout_gravity="center"
        android:layout_marginTop="10dp"/>

</LinearLayout>

package com.example.myapplication1;

import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private TextView textView;
    private String[] sexArry= {"男", "女"};
    int sex = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.bt).setOnClickListener(this);
        textView = (TextView) findViewById(R.id.tv);
    }

    @Override
    public void onClick(View v) {
        AlertDialog dialog;
        AlertDialog.Builder builder=new AlertDialog.Builder(this)
                .setTitle("选择性别")
                .setIcon(R.mipmap.ic_launcher)
                .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();//关闭对话框
                        if (sex==1){
                            textView.setText("您的性别是：女");
                        }else{
                            textView.setText("您的性别是：男");
                        }
                    }
                })
                //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();
    }
}

 

 

 

 

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=".MainActivity"
    >
    <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="#000000"
        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="#000000"
        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>

 

 

 

 

4.教材p76页 图3—17购物商城界面

<?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"
    android:orientation="vertical"
    tools:context=".Main1Activity">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="45dp"
        android:text="购物商城"
        android:textSize="18sp"
        android:background="#FF8F03"
        android:gravity="center"/>
    <ListView
        android:id="@+id/lv_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

<?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"
    android:padding="16dp"
    tools:context=".Main1Activity">
    <ImageView
        android:id="@+id/iv"
        android:layout_height="120dp"
        android:layout_width="90dp"
        android:layout_centerVertical="true"/>

    <RelativeLayout
        android:id="@+id/rl_1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:layout_toRightOf="@+id/iv"
        android:layout_centerVertical="true">
        <TextView
            android:id="@+id/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="桌子"
            android:textSize="21sp"
            android:textColor="#000000"/>
        <TextView
            android:id="@+id/tv_price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="价格："
            android:textSize="21sp"
            android:layout_marginTop="10dp"
            android:layout_below="@+id/title"
            android:textColor="#4A13B6"/>
        <TextView
            android:id="@+id/price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1000"
            android:textSize="20sp"
            android:layout_below="@+id/title"
            android:layout_toRightOf="@+id/tv_price"
            android:textColor="#4A13B6"
            android:layout_marginTop="10dp"
            />
    </RelativeLayout>


</RelativeLayout>

package com.example.myapplication1;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

public class Main1Activity extends Activity {
    private ListView mListView;
    private String[] titles = {"桌子", "苹果", "蛋糕", "线衣", "猕猴桃", "围巾"};
    private String[] prices = {"1800元", "10/kg", "300元", "350元", "10/kg", "280元"};
    private int[] icons = {R.drawable.table, R.drawable.apple, R.drawable.cake, R.drawable.wireclothes, R.drawable.kiwifruit, R.drawable.scarf};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mListView=findViewById(R.id.lv_1);
        MyBaseAdapter mAdapter=new MyBaseAdapter();
        mListView.setAdapter(mAdapter);
    }
    class MyBaseAdapter extends BaseAdapter {

        @Override
        public int getCount() {
            return titles.length;
        }

        @Override
        public Object getItem(int position) {
            return titles[position];
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View view = View.inflate(Main1Activity.this, R.layout.activity_main1, null);
            TextView title =(TextView) view.findViewById(R.id.title);
            TextView price = (TextView) view.findViewById(R.id.price);
            ImageView iv = (ImageView) view.findViewById(R.id.iv);
            title.setText(titles[position]);
            price.setText(prices[position]);
            iv.setBackgroundResource(icons[position]);
            return view;
        }
    }

}