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 com.example.wl1; 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.Button; import android.widget.Toast; 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(); } }
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"?> <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:layout_marginTop="20dp" android:layout_gravity="center"/> </LinearLayout> package com.example.wl4; 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.Toast; public class MainActivity extends AppCompatActivity implements View.OnClickListener { int sex = 0; private String x[] = {"你选择了男","你选择了女"}; @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){ AlertDialog dialog; AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle("性别"); builder.setSingleChoiceItems(new String[]{"男", "女"}, 0, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { sex = i; // Toast.makeText(MainActivity.this,Arr[i], Toast.LENGTH_SHORT).show(); } }); builder.setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { // final String items[]={"男","女"}; Toast.makeText(MainActivity.this,x[sex], Toast.LENGTH_SHORT).show(); dialog.dismiss(); } }); builder.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)
<?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" android:background="#5510F510"> <TextView android:id="@+id/tv" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="1.textview显示文本信息" android:gravity="center" android:layout_marginTop="10dp" android:textSize="20sp" android:textColor="#FFFDB371" /> <Button android:id="@+id/bt" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="2.按钮" android:layout_marginTop="20dp" android:layout_gravity="center" /> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="输入信息" android:textColor="#000000" android:textSize="20sp" android:textStyle="italic" /> <RadioButton android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/rbth" android:textSize="25dp" android:text="男"/> <RadioButton android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="25dp" android:text="女"/> <CheckBox android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/like_shuttlecock" android:text="电脑" android:textSize="18sp" /> <CheckBox android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/like_basketball" android:text="手机" android:textSize="18sp"/> </>
4.教材p76页 图3—17购物商城界面
<?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" android:orientation="vertical" tools:context=".MainActivity"> <ListView android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/lv" android:listSelector="#fefefefe"> </ListView> <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <ImageView android:id="@+id/iv" android:layout_width="120dp" android:layout_height="90dp" android:layout_centerVertical="true" ></ImageView> <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:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/title" android:textSize="21sp" android:textColor="#000000" android:text="桌子"></TextView> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/prices" android:textSize="21sp" android:layout_marginTop="10dp" android:layout_below="@id/title" android:textColor="#000000" android:text="价格"></TextView> <TextView android:id="@+id/price" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="1800" android:textSize="16sp" android:layout_below="@+id/title" android:layout_toRightOf="@+id/prices" android:textColor="#FF716C6D" android:ellipsize="end" android:layout_marginTop="10dp"></TextView> </RelativeLayout> </RelativeLayout> import android.os.Bundle; //import android.widget.ListAdapter; import android.widget.ListView; 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.a,R.drawable.d,R.drawable.b,R.drawable.e,R.drawable.f,R.drawable.c}; @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 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.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; } } }
