java - 对字符串进行删除前缀的操作

Question

final Intent mainIntent=new Intent(Intent.ACTION_MAIN,null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER) ;
final PackageManager pm = getApplicationContext().getPackageManager();
ArrayList<ResolveInfo> listP= (ArrayList<ResolveInfo>) pm.queryIntentActivities( mainIntent, 0);

//Drawable iconApp = resolveInfo.activityInfo.loadIcon(getPackageManager());

ApplicationAdapter adapter = new ApplicationAdapter(this, listP);

adapter.addListener(this);
ListView list = (ListView)findViewById(R.id.list);

list.setAdapter(adapter);

此代码显示所有可用的应用程序，但我想处理结果。在每一行上都有 com.android.*，这就是我想要剪切的部分。

问题是当我尝试使用 substring(10) 时，它不会改变结果。

我尝试了这种方式，并且通过 Log 我成功获得了子字符串，但是当我将其显示在屏幕上时，它只是向我显示了带有所有按钮的另一个布局 我几乎用这段代码得到了它，我用日志显示了我想要在屏幕上显示的内容，但是只有一 block 黑板，而我用日志得到了正确的结果 我看不出原因

public void onCreatebis() {

        setContentView(R.layout.main);
        final Intent mainIntent=new Intent(Intent.ACTION_MAIN,null);
        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER) ;
        final PackageManager pm = getApplicationContext().getPackageManager();
        ArrayList<ResolveInfo> listP= (ArrayList<ResolveInfo>) pm.queryIntentActivities( mainIntent, 0);
        final int trimLength = "com.android.".length();
        ArrayList<String> maliste = new ArrayList();
        int size=listP.size();
        size=maliste.size();
       //String []maliste=new String[listP.size()];
        // Loop over each item.
        for (ResolveInfo info : listP) {
            // Get the (full, qualified) package name.
            String packag = info.activityInfo.applicationInfo.packageName;

            // Now, trim it with substring and the trim length.
            String trimmed = packag.substring(trimLength);
            for(int i=0;i<maliste.size();i++){
                maliste.set(i, trimmed);
            }
            Log.v("trimmed", trimmed);

            // [ do whatever you want with the trimmed name ]
        }




        ArrayAdapter<String> adapter2 = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, maliste);

        ListView list = (ListView)findViewById(R.id.list);

        list.setAdapter(adapter2);

Answer 1

您使用substring的想法是正确的。以下是我的做法:

// Get the length of text to trim.
final int trimLength = "com.android.".length();

// Loop over each item.
for (ResolveInfo info : listP) {
    // Get the (full, qualified) package name.
    String package = info.activityName.packageName;

    // Now, trim it with substring and the trim length.
    String trimmed = package.substring(trimLength);

    // [ do whatever you want with the trimmed name ]
}

trimLength 的值计算为 12，所以我不确定你是如何得到 10 的，但这应该可行。