java - 在通知区域显示加载活动进度条

Question

我想在通知区域放置一个进度条，当用户切换到另一个活动时；在加载时间显示进度百分比和通知区域的值。

我怎样才能做到这一点 ？

Answer 1

您可以通过以下方式做到这一点使用进度条的关键是使用“线程”运行您的时间消耗任务，并使用另一个“线程”相应地更新进度条状态。阅读代码的注释，它应该是不言自明的。

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.os.Handler;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;

public class MyAndroidAppActivity extends Activity {

    Button btnStartProgress;
    ProgressDialog progressBar;
    private int progressBarStatus = 0;
    private Handler progressBarHandler = new Handler();

    private long fileSize = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        addListenerOnButton();

    }

    public void addListenerOnButton() {

        btnStartProgress = (Button) findViewById(R.id.btnStartProgress);
        btnStartProgress.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                // prepare for a progress bar dialog
                progressBar = new ProgressDialog(v.getContext());
                progressBar.setCancelable(true);
                progressBar.setMessage("File downloading ...");
                progressBar.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
                progressBar.setProgress(0);
                progressBar.setMax(100);
                progressBar.show();

                // reset progress bar status
                progressBarStatus = 0;

                // reset filesize
                fileSize = 0;

                new Thread(new Runnable() {
                    public void run() {
                        while (progressBarStatus < 100) {

                            // process some tasks
                            progressBarStatus = doSomeTasks();

                            // your computer is too fast, sleep 1 second
                            try {
                                Thread.sleep(1000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }

                            // Update the progress bar
                            progressBarHandler.post(new Runnable() {
                                public void run() {
                                    progressBar.setProgress(progressBarStatus);
                                }
                            });
                        }

                        // ok, file is downloaded,
                        if (progressBarStatus >= 100) {

                            // sleep 2 seconds, so that you can see the 100%
                            try {
                                Thread.sleep(2000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }

                            // close the progress bar dialog
                            progressBar.dismiss();
                        }
                    }
                }).start();

            }

        });

    }

    // file download simulator... a really simple
    public int doSomeTasks() {

        while (fileSize <= 1000000) {

            fileSize++;

            if (fileSize == 100000) {
                return 10;
            } else if (fileSize == 200000) {
                return 20;
            } else if (fileSize == 300000) {
                return 30;
            }
            // ...add your own

        }

        return 100;

    }

}

打开“layout/main.xml”文件，添加普通按钮进行演示。

<Button
    android:id="@+id/btnStartProgress"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Download File" />

Answer 2

要显示通知：

NotificationManager notificationManager = (NotificationManager) mContext
            .getSystemService(NOTIFICATION_SERVICE);


        Notification updateComplete = new Notification();
        updateComplete.icon = android.R.drawable.stat_notify_sync;
        updateComplete.tickerText = mContext
            .getText(R.string.app_name);
        updateComplete.when = System.currentTimeMillis();

        Intent notificationIntent = new Intent(mContext,
                MainActivity.class);
            PendingIntent contentIntent = PendingIntent.getActivity(mContext, 0,
                notificationIntent, 0);

            String contentTitle = mContext.getText(R.string.app_name)
                    .toString();
                String contentText;

                    contentText = mContext.getText(
                        R.string.yes).toString();

                updateComplete.setLatestEventInfo(mContext, contentTitle,
                    contentText, contentIntent);

                notificationManager.notify(progressBarStatus, updateComplete);

了解更多信息：

http://mobile.tutsplus.com/tutorials/android/android-fundamentals-status-bar-notifications/