有人能告诉我如何将参数传递给线程吗?
另外,匿名类是如何工作的?
有人能告诉我如何将参数传递给线程吗?
另外,匿名类是如何工作的?
当前回答
参数通过start()和run()方法传递:
// Tester
public static void main(String... args) throws Exception {
ThreadType2 t = new ThreadType2(new RunnableType2(){
public void run(Object object) {
System.out.println("Parameter="+object);
}});
t.start("the parameter");
}
// New class 1 of 2
public class ThreadType2 {
final private Thread thread;
private Object objectIn = null;
ThreadType2(final RunnableType2 runnableType2) {
thread = new Thread(new Runnable() {
public void run() {
runnableType2.run(objectIn);
}});
}
public void start(final Object object) {
this.objectIn = object;
thread.start();
}
// If you want to do things like setDaemon(true);
public Thread getThread() {
return thread;
}
}
// New class 2 of 2
public interface RunnableType2 {
public void run(Object object);
}
其他回答
Android专用
为了回调的目的,我通常使用输入参数实现自己的泛型Runnable:
public interface Runnable<TResult> {
void run(TResult result);
}
用法很简单:
myManager.doCallbackOperation(new Runnable<MyResult>() {
@Override
public void run(MyResult result) {
// do something with the result
}
});
在经理:
public void doCallbackOperation(Runnable<MyResult> runnable) {
new AsyncTask<Void, Void, MyResult>() {
@Override
protected MyResult doInBackground(Void... params) {
// do background operation
return new MyResult(); // return resulting object
}
@Override
protected void onPostExecute(MyResult result) {
// execute runnable passing the result when operation has finished
runnable.run(result);
}
}.execute();
}
要么编写一个实现Runnable的类,并在适当定义的构造函数中传递所需的任何内容,要么编写一个使用适当定义的构造函数来扩展Thread的类,该构造函数使用适当的参数调用super()。
在类中创建一个局部变量,用于扩展Thread或实现Runnable。
public class Extractor extends Thread {
public String webpage = "";
public Extractor(String w){
webpage = w;
}
public void setWebpage(String l){
webpage = l;
}
@Override
public void run() {// l is link
System.out.println(webpage);
}
public String toString(){
return "Page: "+webpage;
}}
通过这种方式,您可以在运行变量时传递变量。
Extractor e = new Extractor("www.google.com");
e.start();
输出:
"www.google.com"
你需要在构造函数中将参数传递给Runnable对象:
public class MyRunnable implements Runnable {
public MyRunnable(Object parameter) {
// store parameter for later user
}
public void run() {
}
}
并这样调用它:
Runnable r = new MyRunnable(param_value);
new Thread(r).start();
您可以扩展Thread类或Runnable类,并根据需要提供参数。文档中有一些简单的例子。我将把它们移植到这里:
class PrimeThread extends Thread {
long minPrime;
PrimeThread(long minPrime) {
this.minPrime = minPrime;
}
public void run() {
// compute primes larger than minPrime
. . .
}
}
PrimeThread p = new PrimeThread(143);
p.start();
class PrimeRun implements Runnable {
long minPrime;
PrimeRun(long minPrime) {
this.minPrime = minPrime;
}
public void run() {
// compute primes larger than minPrime
. . .
}
}
PrimeRun p = new PrimeRun(143);
new Thread(p).start();