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 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)
<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_1" android:layout_width="wrap_content" android:layout_height="100dp" android:text="单选框" android:gravity="center" android:layout_marginTop="50dp" android:layout_gravity="center"> </Button> </LinearLayout>
package itcast.cn; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.os.Bundle; import android.view.View; import android.widget.Toast; public class Main2Activity extends Activity implements View.OnClickListener{ private int i=1; private int i1[]={1,2}; protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main2); findViewById(R.id.bt_1).setOnClickListener(this); } public void onClick(View v){ AlertDialog dialog; AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle("你的性别是?"); builder.setSingleChoiceItems(new String[]{"女","男"},i,new DialogInterface.OnClickListener(){ public void onClick(DialogInterface dialog,int which){ i=which; } }); builder.setPositiveButton("确定", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { if (i==1){ Toast.makeText(Main2Activity.this,"你选择了男",Toast.LENGTH_SHORT).show(); }else{ Toast.makeText(Main2Activity.this,"你选择了女",Toast.LENGTH_SHORT).show(); } dialog.dismiss(); } }); builder.setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); dialog = builder.create(); dialog.show(); } }
![](https://img2020.cnblogs.com/blog/2322159/202109/2322159-20210924221547350-1442255668.png)
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; } } }
<?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/gouqu" android:layout_width="match_parent" android:layout_height="50dp" android:background="#E91E63" android:text="购物商城" android:textSize="35sp" android:gravity="center" /> <ListView android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/lv" android:layout_below="@id/gouqu"/> </RelativeLayout>
<?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"> <ImageView android:layout_width="200dp" android:layout_height="200dp" android:id="@+id/shop_iv" /> <RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent" android:layout_toRightOf="@id/shop_iv" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/name_shop" android:layout_marginTop="50dp" android:layout_marginLeft="15dp" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="价格:" android:id="@+id/pr" android:layout_below="@id/name_shop" android:layout_marginTop="50dp" android:layout_marginLeft="15dp"/> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/price_shop" android:layout_toRightOf="@id/pr" android:layout_below="@id/name_shop" android:layout_marginTop="50dp" android:layout_marginLeft="15dp"/> </RelativeLayout> </RelativeLayout>