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

package com.example.a;

import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AliasActivity;
import android.app.Dialog;
import android.content.DialogInterface;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;

public class MainActivity extends Activity {

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


  public void onBackPressed(){
      AlertDialog dialog;
       AlertDialog.Builder builder = new AlertDialog.Builder(this)
       .setIcon(R.drawable.ic_launcher)
       .setTitle("asd")
       .setMessage("sadsads")
       .setPositiveButton("quedig", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {
            // TODO Auto-generated method stub
            dialog.dismiss();
            MainActivity.this.finish();
        }
        
        
    })
       .setNegativeButton("quxiao", new DialogInterface.OnClickListener() {
        
        @Override
        public void onClick(DialogInterface dialog, int which) {
            // TODO Auto-generated method stub
            dialog.dismiss();
        }
    });
       dialog=builder.create();
       dialog.show();
  }
  
       
    
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

</RelativeLayout>

 

 

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）

package com.example.a;

import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AliasActivity;
import android.app.Dialog;
import android.content.DialogInterface;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity {

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


  public void onclick(View v){
      AlertDialog dialog;
       AlertDialog.Builder builder = new AlertDialog.Builder(this)
       .setIcon(R.drawable.ic_launcher)
       .setTitle("选择")
       .setMessage("选择男女")
       .setPositiveButton("nan", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {
            // TODO Auto-generated method stub
            Toast.makeText(MainActivity.this, "你选择了男", 10).show();
            dialog.dismiss();
            
        }
        
        
    })
       .setNegativeButton("nv", new DialogInterface.OnClickListener() {
        
        @Override
        public void onClick(DialogInterface dialog, int which) {
            // TODO Auto-generated method stub
            Toast.makeText(MainActivity.this, "你选择了女", 10).show();
            dialog.dismiss();
        }
    });
       dialog=builder.create();
       dialog.show();
  }
  
       
    
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button 
        
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        android:text="按钮"
        android:onClick="onclick"
        />

</RelativeLayout>

 

 

3.布局(详见:Android第五周上机word文档)

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" 
    android:orientation="vertical">

    <TextView 
        android:layout_height="100dp"
        android:layout_width="match_parent"
        android:text="1.显示文本信息"
        />
    <Button 
        
        android:layout_height="100dp"
        android:layout_width="100dp"
        android:text="2.按钮"
        android:onClick="onclick"
        />
    <EditText 
        android:layout_height="100dp"
        android:layout_width="match_parent"
        android:hint="3.输入文本信息"
        />
    <RadioGroup 
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:orientation="horizontal">
        <RadioButton 
            android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:text="nan"/>
        <RadioButton 
            android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:text="nv"/>
        
    </RadioGroup>
    <CheckBox 
       android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:text="DIANNAO"/>
     <CheckBox 
       android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:text="SHOUJI"/>

</LinearLayout>

 

4.教材p76页 图3—17购物商城界面

package com.example.aswork1;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity {

    List<Fruit> list = new ArrayList<Fruit>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initFruit();// 初始化数据源
        ListView listview = (ListView) findViewById(R.id.listView1);// 获取界面上的Listview
        FruitAdapter adapter = new FruitAdapter(this, R.layout.activity_main2, list);
        listview.setAdapter(adapter);

    }

    // 定义数据源，使用集合的方式
    public void initFruit() {
        Fruit apple = new Fruit("苹果", R.drawable.ic_launcher_background);
        Fruit cake = new Fruit("香蕉", R.drawable.ic_launcher_background);
        Fruit scarf = new Fruit("桃子", R.drawable.ic_launcher_background);
        Fruit table = new Fruit("梨", R.drawable.ic_launcher_background);
        list.add(apple);
        list.add(cake);
        list.add(scarf);
        list.add(table);

    }


}
package com.example.aswork1;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.List;

public class FruitAdapter extends ArrayAdapter {
    int resourceid;
    public FruitAdapter(Context context, int resource, List objects) {
        super(context, resource, objects);
        // TODO Auto-generated constructor stub
        this.resourceid = resource;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        Fruit fruit = (Fruit) getItem(position);// 获取当前项的fruit实例
        View view = LayoutInflater.from(getContext()).inflate(resourceid, null);// 实例化一个view，item对象
        ImageView iv = (ImageView) view.findViewById(R.id.fruit_image);// 获取该布局内的Imageview
        TextView tv = (TextView) view.findViewById(R.id.fruit_name);// 获取该布局内的TextView
        iv.setImageResource(fruit.getImageid());//为图片视图设置图片资源
        tv.setText(fruit.getName());//为文本视图设置文本内容
        return view;
    }
}
package com.example.aswork1;

public class Fruit {
    String name;
    int imageid;

    public Fruit(){

    }
    public Fruit(String name, int imageid) {
        super();
        this.name = name;
        this.imageid = imageid;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getImageid() {
        return imageid;
    }
    public void setImageid(int imageid) {
        this.imageid = imageid;
    }

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    </ListView>

</RelativeLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="horizontal">
    <ImageView
        android:id="@+id/fruit_image"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"     />
    <TextView
        android:id="@+id/fruit_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />



</LinearLayout>