android - 如何在任何一个 Activity 中每秒更新标题布局文本并显示在所有屏幕中？

Question

header.xml

<LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >
        <TextView
            android:id="@+id/txtTime"               
            android:layout_width="0dip"
            android:layout_height="fill_parent"
            android:layout_marginRight="10dp"
            android:layout_weight="1"
            android:gravity="right" />
    </LinearLayout>

---

我在我所有的屏幕布局中添加了 header.xml...

 <include
        android:id="@+id/top_header"
        layout="@layout/header" />

现在我想启动 timer 并在文本标题 txtTime 中设置每剩余秒数的文本...那么我为哪个屏幕编写倒数计时器代码并设置 textview 所以所有屏幕显示时间都在 textview..

谁能建议我只在一个屏幕上设置文本并在所有屏幕上显示？

谢谢

Answer 1

请尝试下面的代码。它将解决您的问题。

按照以下步骤操作。

1) Make one BaseActivity Class.
2) Make One MainActivity Class and extend BaseActivity.
3) Make another SecondActivity class and extend BaseActivity.

我在这里发布您需要的所有类(class)。

我在 BaseActivity 中做什么？

I create one Countdown Timer class called MyCount which will display the remaining time . I create one boolean flag which set false by default . so when user call setHeading() function of BaseActivity it will check the falg if it false then start the timer and if it is true then again set the timer and starts again .

基础 Activity

import android.app.Activity;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.widget.TextView;

public abstract class BaseActivity extends Activity
{
    private TextView textView = null;
    public static MyCount counter = null; 
    private static boolean flag = false;
    private static long millisUntilFinishedVariable = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);

    }

    protected void setHeading(String message) 
    {
        if(textView == null)
        {
            textView = (TextView)findViewById(R.id.textView);
            if(textView != null)
                textView.setText(message);

            if(flag == false)
            {
                counter = new MyCount(30000, 1000);
                counter.start();
            }
            else
            {
                            counter.cancel();
                counter = new MyCount(millisUntilFinishedVariable, 1000);
                counter.start();
            }
        }
    }

    // countdowntimer is an abstract class, so extend it and fill in methods
    public class MyCount extends CountDownTimer
    {

        public MyCount(long millisInFuture, long countDownInterval) 
        {
            super(millisInFuture, countDownInterval);
        }

        @Override
        public void onFinish() 
        {
            textView.setText("done!");   //TextView object should be defined in onCreate
            flag = false;
        }

        @Override
        public void onTick(long millisUntilFinished) 
        {
            millisUntilFinishedVariable = millisUntilFinished;
            flag = true;
            textView.setText("Left:" + millisUntilFinished/1000);// This will be called every Second.
        }
    }
} 

主要 Activity

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends BaseActivity 
{
    private Button buttonClick = null;
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setHeading("Text From Main Activity"); 

        buttonClick = (Button)findViewById(R.id.buttonClick);
        buttonClick.setOnClickListener(new OnClickListener() 
        {
            @Override
            public void onClick(View arg0) 
            {
                startActivityForResult(new Intent(MainActivity.this,SecondActivity.class), 0);
            }
        });
    }
}

activity_main.xml

<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" >

   <include layout="@layout/header"/>

   <Button
       android:id="@+id/buttonClick"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:layout_alignParentLeft="true"
       android:layout_alignParentTop="true"
       android:layout_marginLeft="96dp"
       android:layout_marginTop="68dp"
       android:text="Second Activity" />

</RelativeLayout>

第二个 Activity

import android.os.Bundle;

public class SecondActivity extends BaseActivity 
{
    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second_activity);
        setHeading("From Second Activity");
    }
}

second_activity.xml

<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" >

   <include layout="@layout/header"/>

</RelativeLayout>

header.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" >


    <TextView 
        android:id="@+id/textView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textSize="18.0sp"/>

</LinearLayout>