我想这样做,只需点击一下按钮,就会有一条弹出消息。
现在,只要我打开应用程序,弹出窗口就会出现。
BTW我想触发弹出窗口的按钮是main.xml中的about按钮
这是我的main.xml(包含布局内容):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/main"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#3DE400"
android:orientation="vertical" >
<!-- background originally #d78a00 -->
<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="60dp"
android:fontFamily="sans-serif-condensed"
android:paddingLeft="10dp"
android:text="Sample App"
android:textColor="#FFF"
android:textSize="60sp" />
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-condensed"
android:paddingLeft="10dp"
android:text="@string/creator"
android:textColor="#FFF"
android:textSize="20dp" />
<Button
android:id="@+id/about"
android:layout_width="123dp"
android:layout_height="wrap_content"
android:layout_marginTop="50dp"
android:background="@android:color/transparent"
android:fontFamily="sans-serif-condensed"
android:gravity="left"
android:paddingLeft="10dp"
android:text="@string/about"
android:textColor="#FFF"
android:textSize="40dp"
android:onClick="show" />
</LinearLayout>
这是我的MainActivity.java:
package com.pranavsanghvi.sampleappv4;
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.view.Menu;
import android.widget.Toast;
import android.content.DialogInterface;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
AlertDialog.Builder alert = new AlertDialog.Builder(MainActivity.this);
alert.setTitle("About");
alert.setMessage("Sample About");
alert.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick (DialogInterface dialog, int id) {
Toast.makeText (MainActivity.this, "Success", Toast.LENGTH_SHORT) .show();
}
});
alert.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Toast.makeText(MainActivity.this, "Fail", Toast.LENGTH_SHORT) .show();
}
});
alert.show();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
答案 0 :(得分:0)
如果要在约按钮上显示弹出窗口,请在onCreate()
Button aboutButton = (Button) findViewById(R.id.about);
aboutButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
alert.show();
}
});
从onCreate();
中删除alert.show();
更新: -
您是否收到警报无法解决?如果是,那么要么使全局警报,即在onCreate()
public class MainActivity extends Activity {
AlertDialog.Builder alert;
@Override
protected void onCreate(Bundle savedInstanceState) {
// code
alert = new AlertDialog.Builder(MainActivity.this);
// code
或将其作为最终版本
final AlertDialog.Builder alert = new AlertDialog.Builder(MainActivity.this);
同时删除alert.show();
onCreate();
答案 1 :(得分:0)
首先,在MainActivity中声明警报和按钮:
public class Mainactivity extends Activity {
private AlertDialog.Builder alert;
private Button btAbout;
//rest of the code
}
然后,在onCreate()中,像你一样创建你的警报,除了这一行:
alert.show(); // <--- remove this line as not to show the alert immediately
因为您已经声明了全局警报,所以请记住在此处删除AlertDialog.Builder,而不是:
AlertDialog.Builder alert = new AlertDialog.Builder(MainActivity.this);
alert.setTitle("About");
//rest of the code
你应该:
alert = new AlertDialog.Builder(MainActivity.this);
alert.setTitle("About");
//rest of the code
接下来,获取关于按钮的句柄:
btAbout = (Button) findViewById(R.id.about);
将onClickListener设置为按钮:
btAbout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//when this button is clicked, show the alert
alert.show();
}
});
所有这些都在onCreate()中。现在,当单击按钮时,将显示您的警报。