android:onClick="order"是什么作用
时间: 2023-12-11 19:01:52 浏览: 21
`android:onClick="order"` 是一个 XML 属性,用于在 Android 应用程序中为按钮或其他可点击视图指定单击事件的处理程序方法。当用户单击与此属性关联的视图时,该属性中指定的方法将被调用。在此示例中,单击按钮后将调用名为 "order" 的方法。需要注意的是,该方法必须在与该视图相关联的 Activity 或 Fragment 中进行定义,并且必须具有以下签名:`public void order(View view) {}`。
相关问题
用Android Studio写一个流量监控程序,可以在另一个界面实现分时间段查询流量使用情况和流量统计,发送完整代码
好的,以下是一个简单的流量监控程序的完整代码:
MainActivity.java
```
import android.content.Intent;
import android.net.TrafficStats;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
private int uid;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
uid = android.os.Process.myUid();
}
public void onTimeButtonClick(View view) {
long startTime = System.currentTimeMillis() - 1000 * 60 * 60;
long endTime = System.currentTimeMillis();
long rxBytes = TrafficStats.getTotalRxBytes() - TrafficStats.getUidRxBytes(uid, startTime, endTime);
long txBytes = TrafficStats.getTotalTxBytes() - TrafficStats.getUidTxBytes(uid, startTime, endTime);
TextView text = findViewById(R.id.text);
text.setText("当前时间段内的流量使用情况:\n接收:" + rxBytes + " 字节\n发送:" + txBytes + " 字节");
}
public void onTotalButtonClick(View view) {
long totalRxBytes = TrafficStats.getTotalRxBytes();
long totalTxBytes = TrafficStats.getTotalTxBytes();
TextView text = findViewById(R.id.text);
text.setText("总的流量使用情况:\n接收:" + totalRxBytes + " 字节\n发送:" + totalTxBytes + " 字节");
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_statistics:
Intent intent = new Intent(this, StatisticsActivity.class);
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
```
activity_main.xml
```
<?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"
android:orientation="vertical"
android:padding="16dp"
tools:context=".MainActivity">
<TextView
android:id="@+id/text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
android:textSize="18sp" />
<Button
android:id="@+id/time_button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
android:text="时间段查询"
android:onClick="onTimeButtonClick" />
<Button
android:id="@+id/total_button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="总流量查询"
android:onClick="onTotalButtonClick" />
</LinearLayout>
```
StatisticsActivity.java
```
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import androidx.appcompat.app.AppCompatActivity;
public class StatisticsActivity extends AppCompatActivity {
private SQLiteDatabase db;
private SimpleCursorAdapter adapter;
private ListView listView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_statistics);
listView = findViewById(R.id.list_view);
db = new TrafficStatisticsDbHelper(this).getWritableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM traffic_statistics ORDER BY id DESC", null);
adapter = new SimpleCursorAdapter(this, R.layout.list_item, cursor,
new String[] { "start_time", "end_time", "rx_bytes", "tx_bytes" },
new int[] { R.id.text1, R.id.text2, R.id.text3, R.id.text4 }, 0);
listView.setAdapter(adapter);
}
public void onClearButtonClick(View view) {
db.delete("traffic_statistics", null, null);
adapter.changeCursor(db.rawQuery("SELECT * FROM traffic_statistics ORDER BY id DESC", null));
}
}
```
activity_statistics.xml
```
<?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"
android:padding="16dp">
<ListView
android:id="@+id/list_view"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:divider="#cccccc"
android:dividerHeight="1dp"
android:padding="16dp"
android:textSize="18sp" />
<Button
android:id="@+id/clear_button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="清空记录"
android:onClick="onClearButtonClick" />
</LinearLayout>
```
list_item.xml
```
<?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="wrap_content"
android:orientation="horizontal"
android:padding="8dp">
<TextView
android:id="@+id/text1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="18sp" />
<TextView
android:id="@+id/text2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="18sp"
android:layout_marginStart="16dp" />
<TextView
android:id="@+id/text3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="18sp"
android:layout_marginStart="16dp" />
<TextView
android:id="@+id/text4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="18sp"
android:layout_marginStart="16dp" />
</LinearLayout>
```
TrafficStatisticsDbHelper.java
```
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class TrafficStatisticsDbHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "traffic_statistics.db";
public TrafficStatisticsDbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE traffic_statistics (" +
"id INTEGER PRIMARY KEY AUTOINCREMENT, " +
"start_time INTEGER, " +
"end_time INTEGER, " +
"rx_bytes INTEGER, " +
"tx_bytes INTEGER" +
")");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
```
注意:为了让代码更加清晰,省略了一些异常处理和注释。在实际开发中,请务必添加适当的异常处理和注释。
Android studio关于单词本代码实现
以下是一个简单的 Android Studio 单词本应用程序的代码实现。这个应用程序允许用户输入单词和定义,并将其保存到本地数据库中。
首先,我们需要创建一个数据库类来管理我们的数据:
```java
public class DictionaryDatabase extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "dictionary.db";
private static final int DATABASE_VERSION = 1;
public DictionaryDatabase(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE words (_id INTEGER PRIMARY KEY AUTOINCREMENT, word TEXT, definition TEXT);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS words");
onCreate(db);
}
}
```
这个类创建了一个名为“words”的表,其中包含单词和定义。我们还需要一个类来表示单词和定义:
```java
public class Word {
private long id;
private String word;
private String definition;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getWord() {
return word;
}
public void setWord(String word) {
this.word = word;
}
public String getDefinition() {
return definition;
}
public void setDefinition(String definition) {
this.definition = definition;
}
@Override
public String toString() {
return word + ": " + definition;
}
}
```
接下来,我们需要一个活动来显示单词列表和添加新单词。在这个活动中,我们将使用一个 ListView 来显示单词列表,并使用一个对话框来添加新单词。
```java
public class MainActivity extends AppCompatActivity {
private DictionaryDatabase dictionaryDatabase;
private SimpleCursorAdapter dataAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dictionaryDatabase = new DictionaryDatabase(this);
displayListView();
Button addButton = findViewById(R.id.add_button);
addButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
showAddDialog();
}
});
}
private void displayListView() {
Cursor cursor = dictionaryDatabase.getReadableDatabase().rawQuery("SELECT * FROM words ORDER BY word ASC", null);
String[] columns = new String[] { "word", "definition" };
int[] to = new int[] { R.id.word, R.id.definition };
dataAdapter = new SimpleCursorAdapter(this, R.layout.word_row, cursor, columns, to, 0);
ListView listView = findViewById(R.id.word_list);
listView.setAdapter(dataAdapter);
}
private void showAddDialog() {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Add Word");
View view = LayoutInflater.from(this).inflate(R.layout.add_dialog, null);
builder.setView(view);
final EditText wordEditText = view.findViewById(R.id.word_edit_text);
final EditText definitionEditText = view.findViewById(R.id.definition_edit_text);
builder.setPositiveButton("Add", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String word = wordEditText.getText().toString();
String definition = definitionEditText.getText().toString();
ContentValues values = new ContentValues();
values.put("word", word);
values.put("definition", definition);
dictionaryDatabase.getWritableDatabase().insert("words", null, values);
dataAdapter.changeCursor(dictionaryDatabase.getReadableDatabase().rawQuery("SELECT * FROM words ORDER BY word ASC", null));
}
});
builder.setNegativeButton("Cancel", null);
builder.show();
}
}
```
在这个活动中,我们首先实例化了数据库类,并在 ListView 中显示了单词列表。我们还在“添加”按钮上设置了一个 onClickListener,当用户点击时会显示一个对话框。
最后,我们需要定义单词行的布局和添加对话框的布局:
word_row.xml
```xml
<?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="wrap_content"
android:orientation="vertical"
android:padding="16dp">
<TextView
android:id="@+id/word"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="18sp"
android:textStyle="bold" />
<TextView
android:id="@+id/definition"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="14sp" />
</LinearLayout>
```
add_dialog.xml
```xml
<?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="wrap_content"
android:orientation="vertical"
android:padding="16dp">
<EditText
android:id="@+id/word_edit_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Word" />
<EditText
android:id="@+id/definition_edit_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Definition" />
</LinearLayout>
```
这是一个非常基本的单词本应用程序的代码实现。你可以根据自己的需求对其进行修改和扩展。