每秒更新一个TextView一次，而应用程序正在运行 [英] Updating a TextView once per second while the App is Running

问题描述

我是新来的Andr​​oid编程，但我很熟悉Java等等...

I am new to Android programming, but I'm quite familiar with Java and so...

在这个程序，我需要创造这样一个死亡/出生计数器和一个总人口计数器，所以我需要字符串在活动进行更新每一秒，但我不能看到找到任何解决办法。

In this app, I need to create something like a Death/Birth counter and a Total Population Counter, so I need the String at the Activity to be updated each second, but I can't seen to find any solution.

这是我的主要活动：

public class MainActivity extends ActionBarActivity {

    static int nasc;
    static int mortes;
    static int popTotal;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        nasc = 0;
        mortes = 0;
        popTotal = 0;
        setContentView(R.layout.activity_main);

        final TextView view = new TextView(this);
        Boolean menu = false;
        Handler handler = new Handler();
        while (menu == false) {
            handler.postDelayed(new Runnable() {
                public void run() {
                    view.setText("Births : " + getNasc() + ".");
                    view.append("\n");
                    view.append("Deaths : " + getMortes() + ".");
                    view.append("\n");
                    view.append("Total Population : " + getPopTotal() + ".");
                    setContentView(view);
                }
            }, 1000);
        }
    }

    private int getPopTotal() {
        popTotal = nasc - mortes;
        return popTotal;
    }

    private int getMortes() {
        mortes = (int) (mortes + 1.7);
        return mortes;
    }

    private int getNasc() {
        nasc = nasc + 3;
        return nasc;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.textView) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

有什么我已经做错了吗？

What have I been doing wrong?

推荐答案

您需要做的是去除while循环，只是如果菜单==虚假每一秒与新合计更新UI之后。

What you need to do is remove the while loop, and just re-run the Runnable if menu == false each second after updating the UI with the new totals.

我刚刚得到这个实现通过了Runnable一个成员变量，而不是它是一个匿名类，用一个StringBuilder建立了TextView的文本，并重新运行了Runnable如果菜单工作仍是在每次运行完成假的。

I just got this implementation working by making the Runnable a member variable instead of it being an anonymous class, using a StringBuilder to build up the text for the TextView, and re-running the Runnable if menu is still false at the completion of each run.

public class MainActivity extends ActionBarActivity {

    static int nasc;
    static int mortes;
    static int popTotal;
    TextView view;
    Handler handler;
    Boolean menu;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        nasc = 0;
        mortes = 0;
        popTotal = 0;
        view = (TextView) findViewById(R.id.text);
        menu = false;
        handler = new Handler();
        handler.postDelayed(updateText, 1000);
    }

    public Runnable updateText = new Runnable() {
        @Override
        public void run() {
            StringBuilder sb = new StringBuilder();
            sb.append("Births : " + getNasc() + ".");
            sb.append("\n");
            sb.append("Deaths : " + getMortes() + ".");
            sb.append("\n");
            sb.append("Total Population : " + getPopTotal() + ".");

            view.setText(sb.toString());

            if (menu == false){
                handler.postDelayed(this, 1000);
            }
        }
    };

    //.................

activity_main.xml中：

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" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <TextView android:id="@+id/text" android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</RelativeLayout>

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