Java 处理程序是抽象的，无法实例化
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Handler is abstract ,cannot be instantiated
提问by Chinmay Dabke
I am trying to use a Handlerin my app. But when i instantiate it like this:
我正在尝试Handler在我的应用程序中使用 a 。但是当我像这样实例化它时：
Handler handler = new Handler();
I get the following error.
我收到以下错误。
Gradle: error: Handler is abstract; cannot be instantiated
And when i check the solutions, it asks me to implement these methods:
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) {
}
};
I have never used Handlersbefore and i am using it just to call a method after some delay. To achieve that, I've used:
我以前从未使用Handlers过，我只是在延迟一段时间后使用它来调用方法。为了实现这一点，我使用了：
handler.postDelayed(new Runnable() {
@Override
public void run() {
//Do something after 100ms
}
}, 100);
But it shows the error:
但它显示错误：
Gradle: error: cannot find symbol method postDelayed(<anonymous Runnable>,int)
Please help! Thanks in advance.
请帮忙！提前致谢。
采纳答案by Glenn
It seems you have imported a wrong Handler class
您似乎导入了错误的 Handler 类
import java.util.logging.Handler;
Change it to
将其更改为
import android.os.Handler;
回答by Vahe Gharibyan
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();
};
}
}
回答by Anand Saurabh
In Place Of
代替
import java.util.logging.Handler;
add
添加
import android.os.Handler;
also if you use
如果你使用
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()){....`
它会给出布尔值发现类似错误的错误，所以要么使用 boolean handler = new Handler()... 要么简单地使用 (new Handler()){....`
回答by Sujith Ks
import android.os.Handler; this the handler needed for your purpous. Before importing the Handler class please try to import the above.
导入 android.os.Handler; 这是您的目的所需的处理程序。在导入 Handler 类之前，请尝试导入以上内容。
回答by SPC700
Android SDK auto imports the incorrect one. That's why people have problems.
Android SDK 自动导入不正确的。这就是为什么人们会遇到问题。
