android 设置线程的优先级 (2010-12-09 16:49:34)

有两处API可以设置线程的优先级：

（1）android.os.Process.setThreadPriority (int priority)

或

android.os.Process.setThreadPriority (int tid, int priority)

priority：【-20, 19】，高优先级 -> 低优先级。

（2）java.lang.Thread.setPriority (int priority)

priority：【1, 10】，低优先级 -> 高优先级。

测试后发现，使用android自己的API（第1种方法）设置的优先级，对线程调度影响显著。

=====================

测试代码如下：

=====================

package>

    private>

    @Override

    public>

        a.setOSPriority(Process.THREAD_PRIORITY_LOWEST); // 19

        a.setPriority(Thread.MAX_PRIORITY); // 10

        MyThread>

        b.setOSPriority(Process.THREAD_PRIORITY_URGENT_AUDIO); // -19

        b.setPriority(Thread.MIN_PRIORITY); // 1

        a.start();

        b.start();

    }

    @Override

    public>

        super.onBackPressed();

    }

    private>

        private>

     public MyThread(String>

     }

    @Override

    public void run() {

        Process.setThreadPriority(mOSPriority);

        while(!mNeedExit) {

            mLoopCount ++;

            Math.log(Math.random() * 1000); // calculation test

            Log.d(TAG, new StringBuilder().append(getName())

                    .append(" os priority: ").append(mOSPriority)

                    .append(" java priority: ").append(getPriority())

                    .append(" loop count: ").append(mLoopCount).toString());

            }

            Log.d(TAG, new StringBuilder().append(getName()).append(" exiting...")

                    .append(" os priority: ").append(mOSPriority)

                    .append(" java priority: ").append(getPriority())

                    .append(" loop count: ").append(mLoopCount).toString());

        }

    }

}