Android第三次作业

 

1.返回键实现对话框弹出是否退出应用程序
package com.example.myapplication;

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

import android.content.DialogInterface;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @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)
                .setTitle("普通对话框")
                .setIcon(R.mipmap.ic_launcher)
                .setMessage("是否确定退出应用")
                .setPositiveButton("确定", new DialogInterface.OnClickListener(){
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                        MainActivity.this.finish();



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

                    }

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

    }


}

　　

 

 

 

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

<Button
    android:id="@+id/bt"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="请选择你的性别"
    android:onClick="Clicked"
    android:layout_marginTop="20dp"
    android:layout_gravity="center"/>
</LinearLayout>
package com.example.myapplication;
import androidx.appcompat.app.AppCompatActivity;
 import android.os.Bundle;
 import android.app.AlertDialog;
 import android.content.DialogInterface;
 import android.view.View;
 import android.widget.Toast;
 import android.app.AlertDialog.Builder;
import android.content.DialogInterface.OnClickListener;

        public class MainActivity extends AppCompatActivity {

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




            public void Clicked(View view) {
                AlertDialog.Builder builder = new Builder(this);
                AlertDialog ad = builder.create();
                ad.show();

                builder.setTitle("请选择性别");

               final String[] items = {"男", "女"};

                builder.setSingleChoiceItems(items, -1, new OnClickListener() {

                    @Override
           public void onClick(DialogInterface dialog, int which) {

                               Toast.makeText(
                                                 MainActivity.this,
                                               "您选择的性别是:" + items[which],
                                                Toast.LENGTH_SHORT).show();

                                dialog.dismiss();
                            }
        });

                builder.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"
    android:background="#0DFF18">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:text="1.TextView显示的文本信息"
        android:textSize="29sp"
        android:layout_marginLeft="40dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="30dp"
        android:textColor="#FF0000"
         />
    <Button
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:text="2.按钮"
        android:textSize="30sp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="90dp"
        android:textColor="#FF0000"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="60dp"

        android:text="3.编辑框：请输入信息"
        android:textSize="30sp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="180dp"
        android:textColor="#FF0000"/>
    <RadioGroup
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:orientation="horizontal">
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="4.男"
            android:textSize="30sp"
            android:textColor="#FF0000"
            android:layout_marginTop="250dp"/>
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="女"
            android:textSize="30sp"
            android:textColor="#FF0000"
            android:layout_marginTop="250dp"
            />

    </RadioGroup>
    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="电脑"
        android:textColor="#FF0000"
        android:textSize="30sp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="300dp"/>
    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="手机"
        android:textColor="#FF0000"
        android:textSize="30sp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="340dp"/>

</RelativeLayout>

　　

 

 

4.教材p76页 图3—17购物商城界面
package com.example.andoidtest;
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 MainActivity extends Activity {
    private ListView mListView;
    //商品名称与价格数据集合
    private String [] titles={"桌子","苹果","蛋糕","线衣","猕猴桃","围巾"};
    private String [] prices={"1800","10元/kg","300元","350元","10元/kg","280元"};
    //图片数据集合
    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(MainActivity.this,R.layout.activity_list_item,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;
        }
}
}