Android动画（进度栏）无法顺序加载

Question

I'm attempting to load a series of 5 dots to indicate progress being made however they are not loading sequentially one after another as they should and I'm not sure why.

SOURCE:

public class UpdateActivity extends Activity implements OnClickListener {

    public static int TotalSteps = 8;
    private TelephonyManager tm;

    private Button mUpdateButton = null;
    private Button mAssistUpdateButton = null;
    private Button mAssistInstrButton = null;
    private TextView mReadAgainButton = null;
    private int mInstructionNumber = 0;
    AlertDialog mConfirmAlert = null;
    private NetworkTask task;
    private AnimationDrawable loadingAnimation;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        tm = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
        int networkType = tm.getNetworkType();
        int phoneType = tm.getPhoneType();
        int version = android.os.Build.VERSION.SDK_INT;
        if (phoneType == TelephonyManager.PHONE_TYPE_CDMA
                || (phoneType != TelephonyManager.PHONE_TYPE_GSM
                        && networkType != TelephonyManager.NETWORK_TYPE_GPRS
                        && networkType != TelephonyManager.NETWORK_TYPE_EDGE
                        && networkType != TelephonyManager.NETWORK_TYPE_HSDPA
                        && networkType != TelephonyManager.NETWORK_TYPE_HSPA
                        && networkType != TelephonyManager.NETWORK_TYPE_HSPAP
                        && networkType != TelephonyManager.NETWORK_TYPE_HSUPA
                        && networkType != TelephonyManager.NETWORK_TYPE_UMTS && networkType != TelephonyManager.NETWORK_TYPE_LTE)) {
            // If the phone type is CDMA or
            // the phone phone type is not GSM and the network type is none of
            // the network types indicated in the statement
            // Display incompatibility message
            showAlert(getString(R.string.incomp_sm_dialog));
            // Network type is looked because some tablets have no phone type.
            // We rely on network type in such cases
        } else if (!(tm.getSimState() == TelephonyManager.SIM_STATE_ABSENT
                || (tm.getSimOperator())
                        .equals(getString(R.string.numeric_tmo)) || (tm
                    .getSimOperator()).equals(getString(R.string.numeric_att)))) {
            // if SIM is present and is NOT a T-Mo network SIM,
            // display Error message alert indicating to use SM SIM
            showAlert(getString(R.string.insert_sm_dialog));
        }// No SIM or SIM with T-Mo MNC MCC present
        else if (version < VERSION_CODES.ICE_CREAM_SANDWICH) {
            // Initial UI setup for versions lower than ICS
            setContentView(R.layout.update);
            mUpdateButton = (Button) findViewById(R.id.update_button);

            mUpdateButton.setOnClickListener(this);
        } else {// ICS and up

            // task.execute();

            if ((tm.getSimOperator()).equals(getString(R.string.numeric_tmo))
                    || (tm.getSimOperator())
                            .equals(getString(R.string.numeric_att))) {

                task = new NetworkTask();
                task.execute("");
                // Device has T-Mo network SIM card MCC and MNC correctly
                // populated
                // Reduce number of steps to 6
                TotalSteps = 6;
            }
            //
            // Initial UI setup for ICS and up

            setContentView(R.layout.updating);
            // This image view has the updating text to be progressively
            // updated
            // with dots addition
            ImageView loading = (ImageView) findViewById(R.id.loading_empty1);

            // Set updating button to drawable animation
            loading.setBackgroundResource(R.drawable.updating1);
            loadingAnimation = (AnimationDrawable) loading.getBackground();
            loadingAnimation.setOneShot(false);
            loadingAnimation.start();

            ImageView loading2 = (ImageView) findViewById(R.id.loading_empty2);

            // Set updating button to drawable animation
            loading2.setBackgroundResource(R.drawable.updating2);
            loadingAnimation = (AnimationDrawable) loading2.getBackground();


            loadingAnimation.start();

            ImageView loading3 = (ImageView) findViewById(R.id.loading_empty3);

            // Set updating button to drawable animation
            loading3.setBackgroundResource(R.drawable.updating3);
            loadingAnimation = (AnimationDrawable) loading3.getBackground();


            loadingAnimation.start();


            ImageView loading4 = (ImageView) findViewById(R.id.loading_empty4);

            // Set updating button to drawable animation
            loading4.setBackgroundResource(R.drawable.updating4);
            loadingAnimation = (AnimationDrawable) loading4.getBackground();


            loadingAnimation.start();


            ImageView loading5 = (ImageView) findViewById(R.id.loading_empty5);

            // Set updating button to drawable animation
            loading5.setBackgroundResource(R.drawable.updating5);
            loadingAnimation = (AnimationDrawable) loading5.getBackground();


            loadingAnimation.start();
            // String assistUpdate = getString(R.string.apn_app_text_cta2);
            // CharSequence styledText = Html.fromHtml(assistUpdate);
            // xtView assistText = (TextView)
            // findViewById(R.id.apn_app_text_cta2);
            // sistText.setText(styledText);
            // mAssistUpdateButton = (Button)
            // findViewById(R.id.assist_update_btn);
            //mAssistUpdateButton.setOnClickListener(this);
        }
    }

    public void onClick(View v) {

        if (v == mUpdateButton) {
            // Update button for versions lower than ICS is selected
            // setContentView(R.layout.updating);
            onClickMethod(v);

            Intent i = new Intent(this, ConfigFinalActivity.class);
            startActivity(i);
            finish();
        } else if (v == mAssistUpdateButton) {

            // Update button for ICS and up is selected
            // Get the TextView in the Assist Update UI
            TextView tv = (TextView) findViewById(R.id.apn_app_text_cta2);
            String text = "";
            CharSequence styledText = text;
            switch (mInstructionNumber) {
            case 0:
                // Retrieve the instruction string resource corresponding the
                // 2nd set of instructions
                text = String.format(getString(R.string.apn_app_text_instr),
                        TotalSteps);
                styledText = Html.fromHtml(text);
                // Update the TextView with the correct set of instructions
                tv.setText(styledText);
                // Increment instruction number so the correct instructions
                // string resource can be retrieve the next time the update
                // button is pressed
                mInstructionNumber++;
                break;
            case 1:
                text = getString(R.string.apn_app_text_instr2);
                styledText = Html.fromHtml(text);
                tv.setText(styledText);
                // Increment instruction number so the correct instructions
                // string resource can be retrieve the next time the update
                // button is pressed
                mInstructionNumber++;
                break;
            case 2:
                // Final set of instructions-Change to the corresponding layout

                setContentView(R.layout.assist_instructions);
                String assistUpdateInstr = String.format(
                        getString(R.string.apn_app_text_instr3), TotalSteps);
                styledText = Html.fromHtml(assistUpdateInstr);
                TextView assistInstrText = (TextView) findViewById(R.id.updated_text);
                assistInstrText.setText(styledText);
                mAssistInstrButton = (Button) findViewById(R.id.assist_instr_btn);
                mReadAgainButton = (TextView) findViewById(R.id.read_again_btn);
                mAssistInstrButton.setOnClickListener(this);
                mReadAgainButton.setOnClickListener(this);
            }
        } else if (v == mAssistInstrButton) {
            // "LET'S DO THIS" Button in final instructions screen for ICS and
            // up is selected
            // Create ConfigActivity Intent
            Intent i = new Intent(this, ConfigFinalActivity.class);
            // Invoke ConfigActivity Intent to start the assisted update
            startActivity(i);
            finish();
        } else if (v == mReadAgainButton) {
            // go back to 1st set of instructions if read again is selected
            mInstructionNumber = 0;
            setContentView(R.layout.assist_update);
            String assistUpdate = getString(R.string.apn_app_text_cta2);
            CharSequence styledText = Html.fromHtml(assistUpdate);
            TextView assistText = (TextView) findViewById(R.id.apn_app_text_cta2);
            assistText.setText(styledText);
            mAssistUpdateButton = (Button) findViewById(R.id.assist_update_btn);
            mAssistUpdateButton.setOnClickListener(this);
        }
    }

    public void onClickMethod(View v) {
        mUpdateButton = (Button) findViewById(R.drawable.btn_update_active_hdpi);

    }

    private void showAlert(String message) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setMessage(message).setPositiveButton("OK",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        UpdateActivity.this.finish();
                    }
                });
        mConfirmAlert = builder.create();
        mConfirmAlert.show();
    }

}

updating.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/background"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/updating_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:gravity="center"
        android:text="@string/updating_text"
        android:textColor="#000000"
        android:textSize="14sp" />

    <ImageView
        android:id="@+id/loading_empty1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="150dp"
        android:layout_toLeftOf="@+id/loading_empty2"
        android:layout_marginBottom="20dp"
        android:layout_marginRight="15dp"
        android:background="@drawable/loading_empty"
         />

    <ImageView
        android:id="@+id/loading_empty3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@+id/loading_empty2"
        android:layout_centerHorizontal="true"
        android:background="@drawable/loading_empty"
        android:layout_marginRight="15dp"
        />

    <ImageView
        android:id="@+id/loading_empty2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@+id/loading_empty1"
        android:layout_toLeftOf="@+id/loading_empty3"
        android:background="@drawable/loading_empty"
        android:layout_marginRight="15dp"
         />

    <ImageView
        android:id="@+id/loading_empty4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@+id/loading_empty3"
        android:layout_toRightOf="@+id/loading_empty3"
        android:background="@drawable/loading_empty"
        android:layout_marginRight="15dp"
         />

    <ImageView
        android:id="@+id/loading_empty5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@+id/loading_empty4"
        android:layout_toRightOf="@+id/loading_empty4"
        android:background="@drawable/loading_empty"
         />

</RelativeLayout>

updating1.xml:

<animation-list xmlns:android="http://schemas.android.com/apk/res/android"    
    android:oneshot="false">    
    <item android:drawable="@drawable/loading_empty" android:duration="500" />    
    <item android:drawable="@drawable/loading_full" android:duration="1000" />    
</animation-list>

updating2.xml:

<animation-list xmlns:android="http://schemas.android.com/apk/res/android"    
    android:oneshot="false">    
    <item android:drawable="@drawable/loading_empty" android:duration="1500" />    
    <item android:drawable="@drawable/loading_full" android:duration="2000" />    
</animation-list>

updating3.xml:

<animation-list xmlns:android="http://schemas.android.com/apk/res/android"    
    android:oneshot="false">    
    <item android:drawable="@drawable/loading_empty" android:duration="2500" />    
    <item android:drawable="@drawable/loading_full" android:duration="3000" />    
</animation-list>

updating4.xml:

<animation-list xmlns:android="http://schemas.android.com/apk/res/android"    
    android:oneshot="false">    
    <item android:drawable="@drawable/loading_empty" android:duration="3500" />    
    <item android:drawable="@drawable/loading_full" android:duration="4000" />    
</animation-list>

updating5.xml:

<animation-list xmlns:android="http://schemas.android.com/apk/res/android"    
    android:oneshot="false">    
    <item android:drawable="@drawable/loading_empty" android:duration="4500" />    
    <item android:drawable="@drawable/loading_full" android:duration="5000" />    
</animation-list>

Answer 1

You're using duration wrong. It represents the length of the animation, not the start time. So, get rid of all but one of your xml animations. You can reuse the same for each animation. The key is, the animations need to start at a different time for each dot.

To start the animations at different times, use a Handler , and call postDelayed with a Runnable for every dot, performing the animation on the correct View for the current dot, and reusing the same animation xml. For the first dot use a delay of 0ms or something low, for the second dot use a delay of the 1st dot + total duration of the animation (500ms? 1000ms? whatever you set in your xml...), for the nth dot use a delay of the n-1 dot and the aforementioned total duration of the animation