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 androidx.appcompat.app.AppCompatActivity; import android.app.AlertDialog; import android.content.DialogInterface; import android.os.Bundle; public class a1 extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.a1); } @Override 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(); a1.this.finish(); } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override 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)
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; import android.widget.Toast; public class a2 extends AppCompatActivity implements View.OnClickListener { private TextView textView; private String[] sex1= {"男", "女"}; int sex = 1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.a2); findViewById(R.id.bt).setOnClickListener(this); textView = (TextView) findViewById(R.id.tv); } @Override public void onClick(View v) { AlertDialog dialog; AlertDialog.Builder builder=new AlertDialog.Builder(this) .setTitle("选择性别") .setIcon(R.mipmap.ic_launcher) .setSingleChoiceItems(new String[]{"男", "女"}, sex, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { sex=i; } }) .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { dialog.dismiss(); if (sex==1){ textView.setText("您的性别是:女"); }else{ textView.setText("您的性别是:男"); } } }) //t添加"取消"按钮 .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { dialog.dismiss(); } }); dialog=builder.create(); dialog.show(); } }
<?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" android:orientation="vertical" tools:context=".MainActivity"> <TextView android:id="@+id/tv" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="您的性别是:" android:gravity="center" android:textSize="25sp" android:layout_marginTop="20dp" android:textColor="#000000"/> <Button android:id="@+id/bt" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="选择性别" android:layout_gravity="center" android:layout_marginTop="30dp"/> </LinearLayout>
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" > <TextView android:id="@+id/t_1" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="TixtView显示文本信息" android:textSize="30dp" android:textColor="#F81F1F" android:gravity="center"/> <Button android:id="@+id/bt1" android:layout_width="300dp" android:layout_height="wrap_content" android:text="按钮" android:textSize="30dp" android:textColor="#F81F1F" android:layout_below="@id/t_1" android:layout_centerHorizontal="true"/> <EditText android:id="@+id/e1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@id/bt1" android:hint="输入信息" android:maxLines="2" android:textSize="30dp"/> <RadioButton android:id="@+id/rbtn1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="30dp" android:text="男" android:textColor="#FF8F03" android:layout_below="@id/e1"/> <RadioButton android:id="@+id/rbtn2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="30dp" android:text="女" android:textColor="#FF8F03" android:layout_toRightOf="@id/rbtn1" android:layout_below="@id/e1" android:layout_marginLeft="5dp"/> <CheckBox android:id="@+id/cb1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/rbtn1" android:text="电脑" android:textSize="30dp"/> <CheckBox android:id="@+id/cb2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/cb1" android:text="手机" android:textSize="30dp"/> </RelativeLayout>
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: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_1" android:layout_width="match_parent" android:layout_height="45dp" android:text="购物商城" android:textSize="18sp" android:textColor="#000000" android:background="#FF8F03" android:gravity="center"/> <ListView android:id="@+id/lv_1" android:layout_width="match_parent" android:layout_height="wrap_content"/> </LinearLayout> <?xml version="1.0" encoding="utf-8"?> <RelativeLayout 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=".MainActivity" android:padding="16dp"> <ImageView android:id="@+id/iv" android:layout_width="120dp" android:layout_height="90dp" android:layout_centerVertical="true"/> <RelativeLayout android:id="@+id/rl_1" 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:textColor="#000000" android:textSize="20sp"/> <TextView android:id="@+id/tv_price" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="价格" android:textColor="#FF8F03" android:textSize="20sp" 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="#FF8F03" android:layout_toRightOf="@id/tv_price" android:layout_marginTop="10dp" android:layout_below="@+id/title"/> </RelativeLayout> </RelativeLayout>
package com.example.myapplication; 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 a3 extends Activity { private ListView mListView; 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 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_a4); 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(a3.this,R.layout.a3,null); TextView title=(TextView) view.findViewById(R.id.title); TextView price=(TextView) view.findViewById(R.id.packed); ImageView iv=(ImageView)view.findViewById(R.id.iv); title.setText(titles[position]); price.setText(prices[position]); iv.setBackgroundResource(icons[position]); return view; } }