Question

您是否使用与Android Studio中的方法不同的方法？我有以下主要课程：

package com.example.bluebus;


import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;

import static java.util.concurrent.TimeUnit.SECONDS;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        BeeperControl test = new BeeperControl();
        //test.test();
        //test.test();*/

    }
}

在同一文件夹中我有以下BeeperControl类：

import java.util.concurrent.ScheduledFuture;

import static java.util.concurrent.TimeUnit.SECONDS;

/**
 * Created by Arthur on 1/7/2017.
 */

public class BeeperControl extends AppCompatActivity {
        /*private final ScheduledExecutorService scheduler =
                Executors.newScheduledThreadPool(1);*/
        final TextView text = (TextView) findViewById(R.id.text);
    /*
        public void beepForAnHour() {
            final Runnable beeper = new Runnable() {
                public void run() {
                    text.setText("Hello!");
                }
            };
            final ScheduledFuture<?> beeperHandle =
                    scheduler.scheduleAtFixedRate(beeper, 0, 1, SECONDS);
            scheduler.schedule(new Runnable() {
                public void run() { beeperHandle.cancel(true); }
            }, 60 * 60, SECONDS);
        }*/
        public void test(){
            text.setText("Who are you?");
        }
}

按原样编写时，该应用程序正常工作。但是，当我取消注释test.test（）时，当我尝试在模拟器中运行它时，应用程序会保持关闭状态。从我所看到的情况来看，更新清单可能存在问题，但我不确定如何修复它。任何帮助将不胜感激！

Answer 1

让类中的方法返回值，findbyid将返回null，因为它超出范围。

例如：

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;

import static java.util.concurrent.TimeUnit.SECONDS;

public class MainActivity extends AppCompatActivity {

     @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        BeeperControl test = new BeeperControl();
        TextView text = (TextView) findViewById(R.id.text);
        text.setText(test.test());
        //test.test();*/

    }
}

你的班级：

import java.util.concurrent.ScheduledFuture;

import static java.util.concurrent.TimeUnit.SECONDS;

/**
 * Created by Arthur on 1/7/2017.
 */

public class BeeperControl extends AppCompatActivity {
        /*private final ScheduledExecutorService scheduler =
                Executors.newScheduledThreadPool(1);*/
        /* final TextView text = (TextView) findViewById(R.id.text);^/
    /*
        public void beepForAnHour() {
            final Runnable beeper = new Runnable() {
                public void run() {
                    text.setText("Hello!");
                }
            };
            final ScheduledFuture<?> beeperHandle =
                    scheduler.scheduleAtFixedRate(beeper, 0, 1, SECONDS);
            scheduler.schedule(new Runnable() {
                public void run() { beeperHandle.cancel(true); }
            }, 60 * 60, SECONDS);
        }*/
        public string test(){
            return ("Who are you?");
        }
}

如果您通过引用传递文本（可能会为您执行此操作），这可能对您在任何使用的上下文中使用该类都没有帮助。 R / 普雷斯科特......

在Android Studio中使用其他类

1 个答案: