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.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)
package com.example.myapplication; import androidx.appcompat.app.AlertDialog; import androidx.appcompat.app.AppCompatActivity; import android.content.DialogInterface; import android.os.Bundle; import android.view.View; import android.widget.TextView; public class Main3Activity extends AppCompatActivity implements View.OnClickListener { private TextView textView; private String[] textSizeArr={"男","女"}; int textSize =1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main3); findViewById(R.id.bt).setOnClickListener(this); textView=(TextView)findViewById(R.id.tv); } @Override public void onClick(View V){ final AlertDialog dialog; AlertDialog.Builder builder =new AlertDialog.Builder(this) .setTitle("选择性别") .setIcon(R.mipmap.ic_launcher) .setSingleChoiceItems(new String[]{"男", "女"}, textSize, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialogInterface, int i) { textSize=i; } }) .setPositiveButton("确定",new DialogInterface.OnClickListener(){ @Override public void onClick(DialogInterface dialog,int i){ if (i==1){ textView.setText("您的性别是:男"); }else { textView.setText("您的性别是:女"); } dialog.dismiss(); } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { dialog.dismiss(); } }); dialog=builder.create(); dialog.show(); } }
3.布局(详见:Android第五周上机word文档)
4.教材p76页 图3—17购物商城界面
<?xml version="1.0" encoding="utf-8"?> <LinearLayout 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:orientation="vertical"> <TextView android:id="@+id/tv" android:layout_width="match_parent" android:layout_height="50dp" android:text="购物商城" android:textColor="#E8E3E9" android:background="#C175CE" android:textSize="20sp" android:gravity="center"/> <ListView android:id="@+id/lv" android:layout_width="match_parent" android:layout_height="wrap_content"/> </LinearLayout>
package com.example.listview; 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.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元/kg","300元","350元","10元/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 myAdapter = new MyBaseAdapter(); mListView.setAdapter(myAdapter); } 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 i, View view, ViewGroup viewGroup) { View view1= View.inflate(MainActivity.this,R.layout.list_item,null); TextView title = (TextView)view1.findViewById(R.id.title); TextView price = (TextView)view1.findViewById(R.id.price); ImageView iv = (ImageView)view1.findViewById(R.id.iv); title.setText(titles[i]); price.setText(prices[i]); iv.setBackgroundResource(icons[i]); return view1; } } }