Question

我是Android编程新手，但我对Java非常熟悉......

在这个应用程序中，我需要创建一个类似死亡/出生计数器和总人口计数器的东西，所以我需要每秒更新活动中的字符串，但我无法找到任何解决方案。

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);
    }
}

我做错了什么？

Answer 1

您需要做的是删除while循环，只需在使用新总计更新UI后每秒menu == false重新运行Runnable。

我刚刚通过使Runnable成为一个成员变量而不是一个匿名类来实现这个实现，使用StringBuilder为TextView构建文本，并在menu仍然是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); } } }; //.................的情况下重新运行Runnable每次运行结束时都是假的。

<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>

activity_main.xml中：

KeyValuePair<object, object>

Answer 2

试试这个：

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

final TextView view = (TextView)findViewById(R.id.textView_id);

String allText="";
Boolean menu = false;
Handler handler = new Handler();
while (menu == false) {
    handler.postDelayed(new Runnable() {
        public void run() {
            allText+="Births : " + getNasc() + ".";
            allText+="\n";
            allText+="Deaths : " + getMortes() + ".";
            allText+="\n";
            allTExt+="Total Population : " + getPopTotal() + ".";
            view.setText(allText);
            allText="";//reset the string
        }
    }, 1000);
}

}`

在textView声明中的activity_main.xml中添加

<TextView ...
   ... <!--other params that you have set-->
   android:id="@+id/textview_id"
   ... />

Answer 3

尝试这样帮助你

open System

let getValue (t: Type) (v: string) : obj =
    if t = typeof<int> then box ((int) v)
    elif t = typeof<byte> then box ((byte) v)
    elif t = typeof<sbyte> then box ((sbyte) v)
    elif t = typeof<int16> then box ((int16) v)
    elif t = typeof<uint32> then box ((uint32) v)
    elif t = typeof<int64> then box ((int64) v)
    elif t = typeof<uint64> then box ((uint64) v)
    elif t = typeof<double> then box ((double) v)
    elif t = typeof<float32> then box ((float32) v)
    elif t = typeof<decimal> then box ((decimal) v)
    elif t = typeof<char> then box ((char) v)
    elif t = typeof<string> then v :> obj
    else 
        let s = sprintf "Error unknown type %A" t
        raise (ApplicationException(s))

Answer 4

导入此：
// import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; // 并且每隔一分钟使用一次：

ScheduledExecutorService scheduleTaskExecut = Executors.newScheduledThreadPool(5);

    // This run every one minute
    scheduleTaskExecut.scheduleAtFixedRate(new Runnable() {
      public void run() {
//in this Methos Update Your Text as You Need
UpdateYourText();

      }
    }, 0, 1, TimeUnit.MINUTES);

在应用程序运行时每秒更新一次TextView

4 个答案: