Question

我将Android活动作为基本活动，其布局低于布局 -

以下是布局的xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_read_contacts"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="au.com.savedme.ReadContacts">

<ListView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/readContactLv" />

<ProgressBar
    style="?android:attr/progressBarStyle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/readContactPb"
    android:layout_alignParentBottom="false"
    android:layout_alignParentRight="false"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true" />

<android.support.design.widget.FloatingActionButton
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:clickable="true"
    app:fabSize="mini"
    app:srcCompat="@mipmap/ic_cloud_upload_white_24dp"
    android:id="@+id/readContactFab"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true" />

我从另一项活动开始这项活动。我的目标是在onCreate方法中显示进度条，然后加载列表视图，一旦列表视图填充了我想使进度条不可见的项目。

我的问题是

如果我开始填充列表视图，无论我尝试什么，都不会看到进度条。
如果我跳过列表视图，则可以清楚地看到进度条。
如果我填充列表视图，导致之前的活动导致显着延迟，屏幕只会冻结并变黑（并且空白），一旦填充了列表，它就会返回，这不会给出任何用户视觉线索发生的事情（不理想）。

我应该怎么做才能防止这种情况，下面是我的onCreate方法 -

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_read_contacts);

    pb = (ProgressBar) findViewById(R.id.readContactPb);
    pb.setVisibility(View.VISIBLE);

    // Variable initialisations
    contactList = new ArrayList<>();
    contactListTosave = new ArrayList<>();
    mDatabase = FirebaseDatabase.getInstance().getReference();
    userId = FirebaseAuth.getInstance().getCurrentUser().getUid();
    mContactListView = (ListView) findViewById(R.id.readContactLv);
    mContactListView.setOnItemClickListener(onClickListener);
    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.readContactFab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            for (Contact contactToSave:contactListTosave){
                mDatabase.child("contacts").child(userId).child(contactToSave.getFirstName()).setValue(contactToSave);
            }
            Intent i = new Intent(getApplicationContext(),ContactList.class);
            startActivity(i);
        }
    });
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    if (mAdapter == null) {
        mAdapter = new ContactArrayAdapter(ReadContacts.this, 0, contactList);
        mContactListView.setAdapter(mAdapter);
    }
    checkPermissionToReadContact();
}

以下是我的listAdapter的代码 -

import android.content.Context;
import android.os.Build;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

/**
* Created by AppsWise on 15/10/16.
*/

public class ContactArrayAdapter extends ArrayAdapter<Contact> {
    private Context context;
    private List<Contact> contactsProperties;
    private String TAG = "ContactArrayAdapter";

//constructor, call on creation
public ContactArrayAdapter(Context context, int resource, ArrayList<Contact> objects) {
    super(context, resource, objects);
    this.context = context;
    this.contactsProperties = objects;
}

// Called when rendering the view
public View getView(int position, View convertView, ViewGroup parent) {
    // get properties we are displaying
    Contact contact = contactsProperties.get(position);

    //Get inflater and inflate the XML layout for each item
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(MainActivity.LAYOUT_INFLATER_SERVICE);
    View view = inflater.inflate(R.layout.contact_item, null);
    TextView nameText = (TextView) view.findViewById(R.id.nameText);
    TextView contactName = (TextView) view.findViewById(R.id.contactName);
    TextView number = (TextView) view.findViewById(R.id.phoneText);

    String completeName = "";
    if(contact.getFirstName()!=null){
        completeName = contact.getFirstName();
    }
    if(contact.getLastName()!=null){
        completeName += "  "+contact.getLastName();
    }
    if (completeName!=null && completeName.trim().length()>0) {
        if (nameText!=null) {
            nameText.setText(completeName.substring(0,1).toUpperCase());
        }
        contactName.setText(completeName);
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && contact.getIsUploaded() ){
            nameText.setBackgroundColor(context.getColor(R.color.colorAccent));
        }
    }
    number.setText(contact.getPhone());
    return view;
}

}

Answer 1

当您将数据提取到ListView时，请将ListView VISIBILITY保持为GONE。加载ListView后，将ProgressBar VISIBILITY设置为INVISIBLE

Answer 2

尝试以下代码即可问题是一个视图与另一个视图重叠（即进度列表视图）

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
setContentView(R.layout.activity_read_contacts);

mContactListView = (ListView) findViewById(R.id.readContactLv);
mContactListView.setOnItemClickListener(onClickListener);
mContactListView.setVisibility(View.INVISIBLE);

pb = (ProgressBar) findViewById(R.id.readContactPb);
pb.setVisibility(View.VISIBLE);

// Variable initialisations
contactList = new ArrayList<>();
contactListTosave = new ArrayList<>();
mDatabase = FirebaseDatabase.getInstance().getReference();
userId = FirebaseAuth.getInstance().getCurrentUser().getUid();
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.readContactFab);
fab.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        for (Contact contactToSave:contactListTosave){
            mDatabase.child("contacts").child(userId).child(contactToSave.getFirstName()).setValue(contactToSave);
        }
        Intent i = new Intent(getApplicationContext(),ContactList.class);
        startActivity(i);
    }
});
getSupportActionBar().setDisplayHomeAsUpEnabled(true);

if (mAdapter == null) {
    mAdapter = new ContactArrayAdapter(ReadContacts.this, 0, contactList);
    mContactListView.setAdapter(mAdapter);

    //Disabling progress here
    mContactListView.setVisibility(View.VISIBLE);
    pb.setVisibility(View.INVISIBLE);
}
checkPermissionToReadContact();
}

Android基本活动＆amp; ListView - 进度条不可见

2 个答案: