第五六周作业

1.按模拟器上返回键，实现对话框弹出“是否退出应用程序”，如果选择是，退出，选择否，不退出

package com.example.myapplication;


import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.content.DialogInterface;
import android.text.AlteredCharSequence;
import android.view.Menu;

public class MainActivity extends Activity {

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

    }
    @Override
    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() {

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

                    @Override
                    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（参考书上改字体那个案例）

package com.example.myapplication;



import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
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 implements OnClickListener {

    private int num=0;
    private int num1[]={0,1};
    @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 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() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        num=which;
                    }
                })
                .setPositiveButton("确定",new DialogInterface.OnClickListener() {
                    @Override
                    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() {

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

 

 

3.实现如下布局界面

 

 

<?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"
    android:background="#25FA2A"
    android:layout_margin="5dp">

    <TextView
        android:id="@+id/tv_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="1.TextView显示文本信息"
        android:textColor="#F81606"
        android:textSize="20dp"
        android:textStyle="italic"
        android:gravity="center"
        android:layout_marginTop="20dp"/>
    <Button
        android:id="@+id/bu_1"
        android:layout_width="360dp"
        android:layout_height="wrap_content"
        android:text="2.按钮"
        android:textColor="#F81606"
        android:textSize="20dp"
        android:textStyle="bold"
        android:layout_centerHorizontal="true"
        android:layout_below="@id/tv_1"
        android:padding="10dp"/>
    <EditText
        android:id="@+id/et_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="3.编辑框：请输入信息"
        android:textColorHint="#F81606"
        android:textSize="25dp"
        android:layout_below="@id/bu_1"
        android:layout_margin="5dp"
        android:padding="10dp"/>
    <RadioGroup
        android:id="@+id/rg_1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/et_1"
        android:layout_alignLeft="@id/et_1"
        android:orientation="horizontal"
        android:padding="5dp">

        <RadioButton
            android:id="@+id/rb_1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="4.男"
            android:textSize="20dp"
            android:textColor="#F81606" />
        <RadioButton
            android:id="@+id/rb_2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="女"
            android:textSize="20dp"
            android:textColor="#F81606" />
    </RadioGroup>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:layout_below="@id/rg_1"
        android:layout_alignLeft="@id/rg_1">
        <CheckBox
            android:id="@+id/ck_1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="电脑"
            android:textSize="20dp"
            android:textColor="#F81606"
            android:padding="5dp" />
        <CheckBox
            android:id="@+id/ck_2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="手机"
            android:textSize="20dp"
            android:textColor="#F81606"
            android:padding="5dp"/>
    </LinearLayout>

</RelativeLayout>

 

 

4.教材p76页 图3—17购物商城界面

1 package com.example.myapplication;
  2  
  3 import androidx.appcompat.app.AppCompatActivity;
  4  
  5 import android.os.Bundle;
  6 import android.view.View;
  7 import android.view.ViewGroup;
  8 import android.widget.BaseAdapter;
  9 import android.widget.ImageView;
 10 import android.widget.ListView;
 11 import android.widget.TextView;
 12  
 13 public class MainActivity extends AppCompatActivity {
 14     private ListView mListView;
 15     //商品名称与价格数据集合
 16     private String [] titles={"桌子","苹果","蛋糕","线衣","猕猴桃","围巾"};
 17     private String [] prices={"1800元","10元/kg","300元","350元","10元/kg","280元"};
 18     //图片数据集合
 19     private int [] icons={R.drawable.table,R.drawable.apple,R.drawable.cake,R.drawable.wireclothes,R.drawable.kiwifruit,R.drawable.scarf};
 20     @Override
 21     protected void onCreate(Bundle savedInstanceState) {
 22         super.onCreate(savedInstanceState);
 23         setContentView(R.layout.activity_main);
 24         mListView = (ListView) findViewById(R.id.lv);//初始化ListView控件
 25         MyBaseAdapter myAdapter = new MyBaseAdapter();//创建一个Adapter实例
 26         mListView.setAdapter(myAdapter);//设置Adapter
 27     }
 28     class MyBaseAdapter extends BaseAdapter{
 29         @Override
 30         public int getCount() {    //获取item的总数
 31             return titles.length;  //返回ListView Item条目的总数
 32         }
 33         @Override
 34         public Object getItem(int i) {
 35             return titles[i];  //返回Item的数据对象
 36         }
 37         @Override
 38         public long getItemId(int i) {
 39             return i;   //返回Item的id
 40         }
 41         //得到Item的View视图
 42         @Override
 43         public View getView(int i, View view, ViewGroup viewGroup) {
 44             View view1= View.inflate(MainActivity.this,R.layout.list_item,null);
 45             TextView title = (TextView)view1.findViewById(R.id.title);
 46             TextView price = (TextView)view1.findViewById(R.id.price);
 47             ImageView iv = (ImageView)view1.findViewById(R.id.iv);
 48             title.setText(titles[i]);
 49             price.setText(prices[i]);
 50             iv.setBackgroundResource(icons[i]);
 51             return view1;
 52         }
 53     }
 54 }
 55
 78 <?xml version="1.0" encoding="utf-8"?>
 79 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 80     xmlns:app="http://schemas.android.com/apk/res-auto"
 81     xmlns:tools="http://schemas.android.com/tools"
 82     android:layout_width="match_parent"
 83     android:layout_height="match_parent"
 84     tools:context=".MainActivity"
 85     android:orientation="vertical">
 86     <TextView
 87         android:id="@+id/tv"
 88         android:layout_width="match_parent"
 89         android:layout_height="50dp"
 90         android:text="购物商城"
 91         android:textColor="#E8E3E9"
 92         android:background="#FF5722"
 93         android:textSize="20sp"
 94         android:gravity="center"/>
 95     <ListView
 96         android:id="@+id/lv"
 97         android:layout_width="match_parent"
 98         android:layout_height="wrap_content"/>
 99  
100 </LinearLayout>

 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="15dp">

    <ImageView
        android:id="@+id/iv"
        android:layout_width="100dp"
        android:layout_height="80dp"
        android:layout_centerVertical="true"/>
    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_marginLeft="10dp"
        android:layout_toRightOf="@id/iv">
        <TextView
            android:id="@+id/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="桌子"
            android:textSize="20sp"
            android:textColor="#4B4343"/>
        <TextView
            android:id="@+id/tv_p"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="价格"
            android:textSize="20sp"
            android:textColor="#F5A631"
            android:layout_below="@id/title"
            android:layout_marginTop="10dp"/>
        <TextView
            android:id="@+id/price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1800"
            android:textSize="20sp"
            android:textColor="#F5A631"
            android:layout_below="@id/title"
            android:layout_toRightOf="@id/tv_p"
            android:layout_marginTop="10dp"/>

    </RelativeLayout>
</RelativeLayout>