android onresume时view,在onResume中，但通过 invalidate() 方法失败，Android: Graphview更新_android_开发99编程知识库...

我正在研究一個應用程序，其中一個自定義視圖由一些後端邏輯更新。 自定義視圖在 onResume() 方法中更新，但不能通過 view.invalidate(); 更新。 我想讓這個視圖更新按鈕的onclick 。

代碼Fragment如下：public class ChartDemo extends Activity {

private IDemoChart mChart;

Button displayGraph, reloadGraph;

LinearLayout linearLayout;

View view;

Random randomData, randomBattery;

int data, battery;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

mChart = new SalesStackedBarChart();

reloadGraph = (Button) findViewById(R.id.reloadView);

linearLayout = (LinearLayout) findViewById(R.id.linearLayout);

view = new View(ChartDemo.this);

loadGraphWithValues();

reloadGraph.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

view.invalidate();

loadGraphWithValues();

//view = mChart.execute(ChartDemo.this);

}

});

linearLayout.addView(view);

}

public void loadGraphWithValues() {

data = generateDataValue();

battery = generateBatteryValue();

ListData list = new ListData();

list.setData(data, battery);

SalesStackedBarChart.values.add(list);

view = mChart.execute(ChartDemo.this);

}

public int generateBatteryValue() {

//TODO Auto-generated method stub

randomData = new Random();

return randomData.nextInt(100) + 1;

}

public int generateDataValue() {

//TODO Auto-generated method stub

randomBattery = new Random();

return randomBattery.nextInt(100) + 1;

}

public class ListData {

double data;

double battery;

//getter and setter methods..

}

}

請提前致謝。