第5、6周作业

1.返回键实现对话框弹出是否退出应用程序

package itcast.cn;
        import android.app.AlertDialog;
        import android.content.DialogInterface;
        import android.os.Bundle;
        import android.app.Activity;
 
 
public class Main2Activity extends Activity {
 
 
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
    }
 
 
 
    public void onBackPressed(){
        AlertDialog dialog;
        AlertDialog.Builder builder=new AlertDialog.Builder(this)
                .setTitle("普通对话框")
                .setIcon(R.drawable.ic_launcher_background)
                .setMessage("是否确定退出")
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
 
 
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                        Main2Activity.this.finish();}
 
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
 
 
                    public void onClick(DialogInterface dialog, int which) {
                        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）

<?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>

 

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

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#00FF20"
    android:orientation="vertical">
 
    <TextView
        android:layout_width="200dp"
        android:layout_height="50dp"
        android:text="1.TextView显示文本"
        android:textSize="20dp"
        android:gravity="center"
        android:layout_marginTop="50dp"
        android:layout_gravity="center"
        android:textStyle="italic"
        android:textColor="#C00000">
    </TextView>
    <Button
        android:id="@+id/bt_1"
        android:layout_width="250dp"
        android:layout_height="50dp"
        android:text="2.按钮"
        android:textSize="25dp"
        android:textColor="#C00000"
        android:gravity="center"
        android:layout_gravity="center">
    </Button>
<EditText
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:hint="3.编辑框：请输入信息"
    android:textColorHint="#C00000"
    android:layout_marginLeft="20dp"
    android:textSize="25sp"
    android:textStyle="bold">
</EditText>
   <RadioGroup
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:orientation="horizontal">
       <RadioButton
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:text="4.男"
           android:layout_marginLeft="20dp"
           android:textSize="25dp"
           android:textColor="#C00000">
       </RadioButton>
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textStyle="bold"
            android:text="女"
            android:textSize="25dp"
            android:textColor="#C00000"></RadioButton>
   </RadioGroup>
    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="电脑"
        android:layout_marginLeft="20dp"
        android:textSize="25dp"
        android:textColor="#C00000"></CheckBox>
    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="手机"
        android:layout_marginLeft="20dp"
        android:textSize="25dp"
        android:textColor="#C00000"></CheckBox>
</LinearLayout>

　　

 

 

4.教材p76页 图3—17购物商城界面

package com.example.myapplication;
 
import androidx.appcompat.app.AppCompatActivity;
 
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
 
public class MainActivity extends AppCompatActivity {
    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 = (ListView) findViewById(R.id.lv);
        MyBaseAdapter mAdapter = new MyBaseAdapter();
        mListView.setAdapter( mAdapter);
    }
        class MyBaseAdapter extends BaseAdapter {
 
            @Override
            public int getCount() {
                return titles.length;
            }
 
            @Override
            public Object getItem(int i) {
                return titles[i];
            }
 
            @Override
            public long getItemId(int i) {
                return i;
            }
 
            @Override
            public View getView(int i, View view, ViewGroup viewGroup) {
                view = View.inflate(MainActivity.this, R.layout.item, null);
                TextView title = view.findViewById(R.id.name_shop);
                TextView price = view.findViewById(R.id.price_shop);
                ImageView iv = view.findViewById(R.id.shop_iv);
                title.setText(titles[i]);
                price.setText(prices[i]);
                iv.setImageResource(icons[i]);
                return view;
            }
        }
 
}

　　

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<?xml version="1.0" encoding="utf-8"?>
<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=".Demo6Activity"
    android:orientation="vertical">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="45dp"
        android:text="购物商城"
        android:textSize="18sp"
        android:textColor="#FFFFFF"
        android:background="#FF8F03"
        android:gravity="center"/>
    <ListView
        android:id="@+id/lv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

　　

复制代码
<?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="16dp">
    <ImageView
        android:id="@+id/iv"
        android:layout_width="120dp"
        android:layout_height="90dp"
        android:layout_centerVertical="true"/>
    <RelativeLayout
        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="20sp"
            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="20sp"
            android:textColor="#FF8F03"
            android:layout_marginTop="10dp"
            android:layout_below="@id/title"/>
        <TextView
            android:id="@+id/price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1000"
            android:textSize="20sp"
            android:textColor="#38EE74"
            android:layout_below="@id/title"
            android:layout_toRightOf="@id/tv_price"
            android:layout_marginTop="10dp"/>
    </RelativeLayout>

</RelativeLayout>
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