处理程序是抽象的，不能实例化

我试图在我的应用程序中使用 Handler，但是，当我像这样实例化它时:

Handler handler = new Handler();

我得到以下错误:

Error: Handler 是抽象的; 不能实例化

当我检查解决方案时，它要求我实现这些方法:

Handler handler = new Handler() {
@Override
public void close() {
        

}


@Override
public void flush() {


}


@Override
public void publish(LogRecord record) {


}
};

我从来没有使用过 Handlers之前，我使用它只是为了调用一个方法后，一些延迟。为了达到这个目的，我使用了:

handler.postDelayed(new Runnable() {
@Override
public void run() {
//Do something after 100ms
}
}, 100);

但它表明了一个错误:

错误: 无法找到符号方法 postDelayed (，int)

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最佳答案

It seems you have imported a wrong Handler class

import java.util.logging.Handler;

Change it to 

import android.os.Handler;
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    import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;


public class ActionActivity extends ActionBarActivity {


final String LOG_TAG = "myLogs";
TextView tvInfo;
Button btnStart;
Handler h;


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


setContentView(R.layout.action_activity);
tvInfo = (TextView)findViewById(R.id.tvinfo);
btnStart = (Button)findViewById(R.id.btnstart);


h = new Handler() {
public void handleMessage(android.os.Message msg) {
// update TextView
tvInfo.setText("Закачано файлов: " + msg.what);
if (msg.what == 10) btnStart.setEnabled(true);
};
};


}


public void onclick(View v) {
switch (v.getId()) {
case R.id.btnstart:
btnStart.setEnabled(false);
Thread t = new Thread(new Runnable() {
public void run() {
for (int i = 1; i <= 10; i++) {
// some process
downloadFile();
h.sendEmptyMessage(i);


Log.d(LOG_TAG, "i = " + i);
}
}
});
t.start();
break;
case R.id.btnTets:
Log.d(LOG_TAG, "test");
break;
default:
break;
}
}


public void downloadFile(){
try{
TimeUnit.SECONDS.sleep(1);
}
catch (InterruptedException e){
e.printStackTrace();
};
}
}
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In Place Of 

import java.util.logging.Handler;

add

import android.os.Handler;

also if you use 

Handler handler = new Handler() {
@Override
public void close() {


}


@Override
public void flush() {


}


@Override
public void publish(LogRecord record) {


}
};

it will give error that boolean found somthing like error so either use boolean handler = new Handler()... or simply use (new Handler()){....`

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import android.os.Handler; this the handler needed for your purpous. Before importing the Handler class please try to import the above.

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Android SDK auto imports the incorrect one. That's why people have problems.

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It seems like you have implemented the wrong Handler class

import java.util.logging.Handler;

Change it to

import android.os.Handler;


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